PROPERTY  OF 

2^   p.  METCAL.F 


LI  B  R  ARY     OF 


I 

I 


IQ85-IQ56 


c.      ^T    '^ 


r\     <^       r" 


I 


y 


\y 


ELEMENTARY  ENTOMOLOGY 


BY 


E.  DWIGHT  SANDERSON 

DEAN   OF  THE   COLLEGE    OF   AGRICULTURE,  WEST  VIRGINIA   UNIVERSITY 
DIRECTOR  WEST  VIRGINIA  AGRICULTURAL  EXPERIMENT   STATION 

AND 

C.  F.  JACKSON 

PROFESSOR  OF  ZOOLOGY  AND   ENTOMOLOGY,  NEW   HAMPSHIRE    COLLEGE 


GINN  AND   COMPANY 

BOSTON  ■  NEW  YORK  •  CHICAGO  •  LONDON 


COPYRIGHT,  1912,  BY  E.  DWIGHT  SANDERSON  AND  C.  J.  JACKSON 
ALL  RIGHTS  RESERVED 

8,2.7 


TEfte   atfttnaeum   jgregft 

GINN  AND  COMPANY  •  PRO- 
PRIETORS •  BOSTON  •  U.S.A. 


prp:face 

During  recent  years  there  has  been  increasing  demand  for 
short  courses  in  elementary  entomology.  For  several  years  past 
the  authors  have  been  endeavoring  to  present  such  courses  to 
their  students,  but  have  encountered  the  difficulty  that  no  textbook 
was  available  which  met  their  needs.  This  book  is,  therefore,  the 
authors'  effort  to  furnish  such  a  text  for  beginners,  and  if  it  is 
found  useful  to  them  and  to  the  increasing  number  of  teachers 
who  are  endeavoring  to  instruct  them  in  the  subject,  the  authors 
will  feel  well  repaid.  The  work  is  confessedly  very  largely  a  com- 
pilation from  the  works  of  others  (as,  indeed,  any  such  work  must 
be),  and  it  is  obvious  that  many  errors  and  defects  may  have  been 
overlooked,  although  the  authors  have  spared  no  pains  to  eliminate 
them.  To  those  who  observe  such  shortcomings,  or  who  may  be 
able  to  offer  suggestions  for  the  improvement  of  the  book  when 
revised,  the  authors  will  be  under  great  obligation. 

It  was  originally  intended  to  include  several  chapters  treating  of 
the  various  insect  pests  affecting  crops  and  domestic  animals,  but 
it  was  found  that  such  a  work  would  be  too  cumbersome ;  indeed, 
it  is  usually  not  possible  to  cover  both  elementary  and  economic 
entomology  in  a  single  course.  The  economic  side  of  the  subject 
has,  however,  been  made  the  dominant  note  in  the  following  pages, 
and  the  forms  discussed  are  mostly  those  of  economic  importance. 
There  is  a  popular  belief,  often  held  by  young  agricultural  stu- 
dents, that  the  chief  subject  matter  of  a  course  in  entomology 
should  be  a  discussion  of  the  common  injurious  insects.  Expe- 
rience has  shown  that  such  an  idea  is  fallacious,  and  that,  from  the 
standpoint  of  practical  utility  as  well  as  from  that  of  general  cul- 
ture, a  knowledge  of  the  structure,  habits,  and  classes  of  insects 
in  general  is  much  the  more  important  phase  of  entomology  for 
academic  study.    Economic  entomology  is  important  and  should 


iv  ELEMENTARY  ENTOMOLOGY 

not  be  neglected,  but  general  entomology  is  the  foundation  upon 
which  it  must  be  erected,  and  without  a  knowledge  of  the  elements 
of  entomolog}^  a  course  in  economic  entomology  will  have  but 
little  meaning  to  the  average  student,  whereas  if  the  more  general 
knowledge  of  the  subject  has  been  mastered,  the  study  of  the 
various  insect  pests  may  be  profitably  pursued  by  the  individual, 
even  if  he  has  not  been  able  to  take  a  systematic  course  in  that 
phase  of  the  subject. 

Students  should  be  encouraged  to  make  free  use  of  the  standard 
textbooks  for  reference  and  to  aid  in  the  identification  of  speci- 
mens. Much  interest  may  be  added  to  the  course  by  securing  the 
available  entomological  publications  of  the  state  agricultural  experi- 
ment stations  (a  list  of  which  stations  may  be  found  in  the 
Appendix)  and  those  of  the  Bureau  of  Entomology,  United  States 
Department  of  Agriculture,  Washington,  D.C.,  many  of  which  may 
be  had  free  of  charge. 

The  work  outlined  in  the  study  of  life  histories,  in  collecting, 
and  in  the  identification  of  insects  is  necessarily  largely  suggestive. 
The  amount  and  nature  of  such  work  must  depend  upon  the  time 
available,  the  equipment,  the  time  of  year,  and  the  local  surround- 
ings of  the  school,  and  must  be  determined  by  every  teacher  to 
suit  his  own  conditions.  It  should  be  emphasized,  however,  that 
a  maximum  of  laboratory  and  field  work  and  a  minimum  of  book 
work  will  probably  give  the  average  student  a  better  knowledge  of 
insect  life  than  the  opposite  arrangement,  as  the  subject  is  one  in 
which  the  student  must  secure  his  knowledge  directly  from  the 
material,  if  it  is  to  have  much  real  meaning  to  him. 

The  senior  author  is  entirely  responsible  for  the  preparation  of 
Parts  I  and  II,  and  the  junior  author  for  Part  III,  although  they 
have  consulted  together  on  all  parts  of  the  work. 

Many  of  the  half-tone  illustrations  are  from  photographs  by 
the  senior  author  or  from  those  of  Dr.  C.  M,  Weed,  his  prede- 
cessor at  the  New  Hampshire  Agricultural  Experiment  Station, 
while  several  new  line  drawings  have  been  prepared  for  the  work 
by  Alma  Drayer  Jackson  and  Iris  L.  Wood,  for  whose  generous 
aid  the  authors  are  greatly  indebted.    The  remaining  illustrations 


PREFACE  V 

have  been  drawn  from  various  sources,  as  indicated  in  the  titles, 
but  the  authors  are  under  particular  obligations  to  the  following 
persons  for  the  loan  of  cuts  for  electrotyping :  Dr.  L.  O.  Howard, 
Chief  of  the  Bureau  of  Entomolog)',  United  States  Department 
of  Agriculture  ;  Professor  F.  L.  Washburn,  State  Entomologist  of 
Minnesota;  Dr.  J.  B.  Smith,  State  Entomologist  of  New  Jersey; 
Dr.  V.  L.  Kellogg,  of-  Leland  Stanford  Junior  University ;  Dr. 
W.  E.  Britton,  State  Entomologist  of  Connecticut ;  Dr.  E.  P. 
Felt,  State  Entomologist  of  New  York  ;  Professor  G.  W.  Herrick, 
of  Cornell  University ;  Professor  C.  P.  Gillette,  Director  of  the 
Colorado  Agricultural  Experiment  Station  ;  P.  Blakiston's  Son 
&  Co.,  and  D.  Appleton  and  Company. 

The  authors  are  also  greatly  indebted  to  the  following  entomolo- 
gists for  reading  portions  of  the  manuscript  and  criticizing  the  keys 
for  the  identification  of  insects,  which  criticisms  have  added  greatly 
to  the  accuracy  and  reliability  of  the  work  :  Professor  Herbert 
Osborn,  Dr.  C.  T.  Brues,  Mr.  C.  W.  Johnson,  Mr.  Nathan  Banks, 
Dr.  J.  B.  Smith,  Dr.  Harrison  G.  Dyar,  and  Dr.  A.  D,  MacGillivray. 

E.  DWIGHT  SANDERSON 
C.  F.  JACKSON 


CONTENTS . 

CHAPTER  PAGE 

I.    IXTRODUCTION I 

TART  I.    THE  STRUCTURE  AND  GROWTH   OF  INSECTS 

H.  Insects  and  their  Near  Relatives 5 

III.  The  Anatomy  of  Insects  —  External lo 

IV.  The  Anatomy  of  Insects  —  Internal 28 

V.  The  Growth  and  Transformations  of  Insects      ...  45 

PART  II.    THE   CLASSES  OF   INSECTS 

VI.  The  Classification  of  Insects 67 

VII.  Bristletails  and  Springtails  (After A) 73 

VIII.  Cockroaches,   Grasshoppers,    Katydids,   and   Crickets 

{Orthoptera) 76 

IX.  The    Nerve-Winged    Insects,    Scorpion-Flies,    Caddis- 
Flies,  May-Flies,  Stone-Flies,  and  Dragon-Flies  .  89 
X.  TheWhite  Ants,  Book-Lice,  AND  BiRD-LiCE(/^z:^r}'/'7'£'/?.4)  103 
XL  The  True  Bugs,  Aphides,  and  Scale  \'s,sf.ci:s{Hemiptera)  107 
XII.  The  Beetles  {Coleoptera) 136 

XIII.  The  Butterflies  and  Moths  {Lepidoptera)     ....  172 

XIV.  The  Flies,  Mosquitoes,  and  Midges  {Diptera)     .     .     .  218 
XV.  The    Saw-Flies,    Ichneumons,  Wasps,    Bees,    and   Ants 

{Hymenoptera) '   .     .  243 

PART   III.    LABORATORY  EXERCISES 

XVI.  The  External  Anatomy  of  the  Locust 275 

XVII.  A  Comparison  of  the  Different  Types  of  Arthropoda  284 
XVIII.  A  Comparison  of  Different  Types  of  Insects;   Struc- 
ture OF  THE  Bee,  Fly,  and  Beetle 287 

XIX.  The  Internal  Anatomy  of  the  Locust 290 

XX.  The  Mouth-Parts  of  Insects 294 

XXI.  The  Life  History  of  Insects 298 

XXII.  The  Classification  of  Insects 302 

XXIII.  Methods  of  Collecting  Insects 330 

XXIV.  Methods  of  Preserving  and  Studying  Insects     .     .     .  343 

APPENDIX 359 

INDEX  AND   GLOSSARY 363 

vii 


ELEMENTARY  ENTOMOLOGY 


CHAITKR  I 
INTRODUCTION 

A  professor  of  entomology  in  one  of  the  leading  universities 
has  recently  been  quoted  as  saying  that  this  is  "the  age  of  in- 
sects." Doubtless  most  of  us  have  been  accustomed  to  consider  it 
"'  the  age  of  man,"  but  although  man's  sway  is  dominant  in  all 
parts  of  the  earth,  there  is  considerable  evidence  that,  from  a  purely 
biological  standpoint,  insects  are  the  most  characteristic  form  of 
life  of  the  present  age,  and  the  statement  quoted  challenges  our 
attention  for  more  than  a  passing  consideration. 

That  such  a  statement  should  be  made  by  a  well-known  ento- 
mologist, and  should  be  widely  quoted,  is  significant  of  the  present 
attitude  of  the  public  toward  insect  life,  which  has  changed  radi- 
cally during  the  last  generation.  Not  many  years  ago  the  entomol- 
ogist, or  "  bug  collector,"  was  looked  upon  as  a  harmless  individual 
who  amused  himself  with  his  hobby  ;  and  as  he  was  met  with  his 
butterfly  net,  the  passer-by  might  lift  his  eyebrows  as  if  questioning 
whether  a  grown  man  who  would  devote  himself  to  such  insignifi- 
cant creatures  was  really  quite  normal. 

To-day  the  public  has  come  to  appreciate  that  insect  life  plays  a 
most  important  part  in  the  economy  of  our  civilization.  Some  of 
the  problems  which  require  the  work  of  the  trained  entomologist  are 
worthy  of  the  highest  scientific  training  and  best  executive  ability. 

Insects  and  disease.  The  modern  methods  of  sanitation  for  the 
control  of  malarial  fever  and  yellow  fever  involve  the  control  of 
mosquitoes,  which  transmit  these  diseases.  More  and  more  the 
sanitary  measures  which  are  making  the  tropics  habitable  for  the 
more  northern  races  of  man  are  being  made  possible  by  a  knowl- 
edge of  the  relation  of  insect  life  to  the  transmission  of  disease. 
Even  the  common  house-fly,  formerly  considered  a  mere  nuisance. 


2  ELEMENTARY  ENTOMOLOGY 

is  now  known  to  carry  typhoid  fever  and  probably  various  intestinal 
disorders,  to  which  a  large  part  of  our  infant  mortality  is  due  ; 
and  it  has  been  well  said  that,  during  the  Cuban  War,  probably 
more  American  soldiers  were  killed  through  the  agency  of  flies 
carrying  typhoid  germs  than  by  Spanish  bullets. 

Injury  to  crops.  In  their  economic  relations  the  insects  affect- 
ing crops  are  by  all  odds  of  the  most  importance,  many  of  them 
causing  a  loss  of  several  million  dollars  a  year  to  the  farmers  of  the 
United  States.  The  boll  weevil  destroys  over  $25,000,000  worth 
of  cotton  in  Texas  and  Louisiana  alone,  and  10  per  cent  of  the 
wheat  crop  of  the  entire  country,  valued  at  $60,000,000,  is  usually 
destroyed  by  insect  pests.  It  has  been  estimated  by  competent 
authorities  that  10  per  cent  of  the  total  value  of  the  farm  products 
of  the  United  States  is  annually  lost  by  the  ravages  of  insect 
pests,  amounting  to  nearly  $800,000,000  per  annum. 

Injury  to  domestic  animals.  Domestic  animals  are  affected  by 
various  insects,  such  as  the  warble,  or  ox-bot,  and  the  screw  worm, 
—  which  affect  cattle,  —  the  sheep  maggot,  and  many  others,  in- 
cluding the  ticks,  which  carry  Texas  fever  and  other  diseases  ;  so 
that  the  annual  loss  to  live  stock  through  insects  is  estimated  at 
$175,000,000  per  year. 

Injury  to  household  and  stored  goods.  Housekeepers,  manufac- 
turers, and  wholesale  dealers  must  take  into  consideration  the  insect 
life  which  affects  all  sorts  of  vegetable  and  animal  products,  and  the 
aggregate  loss  due  to  the  insect  pests  of  household  and  stored  goods 
must  in  the  aggregate  be  a  considerable  item  in  domestic  economy 
and  mercantile  business. 

Productive  insects.  A  few  insects  contribute  directly  to  the 
wealth  of  the  w^orld  :  the  silkworm  produces  over  $200,000,000 
worth  of  silk  annually,  and  the  product  of  the  busy  honey-bee 
amounts  to  over  $20,000,000  per  year  in  the  United  States  alone. 

Beneficial  insects.  The  direct  relations  of  insects  to  mankind  are 
by  no  means  the  most  important  phases  of  their  ecology.  The  role 
of  insects  in  the  pollenization  of  fruits  and  flowers  is  fundamental 
to  the  successful  fruiting  and  perpetuation  of  a  large  proportion  of 
common  plants.  Again,  a  large  number  of  insects  prey  upon  or  live 
within  the  bodies  of  other  insects,  and  constitute  the  most  impor- 
tant factor  in  the  natural  control  of  injurious  species.    Were  it  not 


INTRODUCTION  3 

for  these  beneficial  forms,  which  prevent  the  normal  increase,  many 
of  our  common  injurious  insects  would  become  so  numerous  as  to 
practically  prohibit  the  growth  of  crops  affected. 

Value  of  study  of  insects.  The  strictly  economic  aspect  of  insect 
life  is  not,  however,  the  only  phase  worthy  of  our  attention  and 
study.  The  apathy  with  which  the  study  of  entomology  was  for- 
merly treated  was  unquestionably  due  to  the  general  lack  of  interest 
in  biology  until  recent  years.  During  the  last  generation  it  has  been 
more  and  more  appreciated  that  man  is  but  a  child  of  nature,  and 
that  he  can  learn  much  in  the  proper  conduct  of  his  affairs  by  a 
study  of  the  laws  of  life  in  general,  whether  of  the  uncivilized  races 
of  mankind,  of  insects,  or  of  microscopic  bacteria  or  protozoa.  Our 
grandfathers  hardly  knew  that  bacteria  existed  ';  to-day  most  of  the 
science  of  pathology,  and  much  of  the  practice  of  medicine,  is  based 
on  an  understanding  of  their  life.  It  would  seem,  therefore,  that 
insect  life  should  furnish  a  large  field  for  the  student  of  general 
biolog}',  and  more  and  more  biological  problems  of  fundamental 
importance  are  being  worked  out  through  studies  of  insects. 

That  this  should  be  the  case  is  extremely  obvious  when  we 
remember  that  there  are  over  300,000  known  species  of  insects, 
including  over  four  fifths  of  the  described  species  of  animals,  and 
that  at  the  rate  at  which  they  are  being  described,  it  has  been  esti- 
mated that  over  a  million  species  exist.  The  immense  number  of 
insects,  both  of  species  and  of  individuals,  is  undoubtedly  due  to 
their  varied  structure,  which  enables  them  to  live  under  all  possible 
conditions.  Thus  the  larv'ae  of  many  different  species  are  adapted 
so  that  they  live  entirely  in  water,  others  bore  in  trees  and  plants, 
some  are  subterranean,  while  still  others  inhabit  the  tissues  of  do- 
mestic animals  or  of  other  insects.  By  the  aid  of  their  wings  the 
adults  spread  rapidly  and  are  thus  able  to  migrate  when  necessity 
arises.  Thus  the  insects  possess  such  diversity  of  structure  and 
habit  that  they  are  able  to  live  under  all  external  conditions,  and 
on  account  of  their  immense  numbers  they  have  been  able  to  adapt 
themselves  to  a  changing  environment  which  would  have  entirely 
obliterated  classes  or  species  few  in  number. 

Not  only  are  insects  the  most  abundant  form  of  animal  life,  but 
they  exhibit  the  highest  degree  of  intelligence  of  any  of  the  lower 
or  invertebrate  animals.    The  wisdom  of  the  ant  and  the  industry 


4  ELEMENTARY  ENTOMOLOGY 

and  domestic  economy  of  the  honey-bee  are  proverbial,  and  new 
observations  are  constantly  showing  the  wonderful  intelligence,  if 
it  may  be  so  called,  evinced  by  many  insects  hitherto  but  little 
known.  No  class  of  animals  is  more  fascinating  or  better  rewards 
the  study  of  the  nature  lover,  as  may  be  slightly  appreciated  from 
the  perusal  of  the  habits  described  in  succeeding  pages. 

It  may  now  be  evident,  in  view  of  the  immense  preponderance 
of  species  and  individuals  of  insects  in  the  animal  kingdom,  and 
their  important  role  in  the  economy  of  nature,  that  there  is  some 
ground  for  describing  the  present  as  "  the  age  of  insects,"  though 
the  term  is  of  course  used  from  a  purely  biological  standpoint. 


PART  I.    THE  STRUCTURE  AND 
GROWTH  OF  INSECTS 


CHAPTER  II 

INSECTS  AND  THEIR  NEAR  RELATIVES 

If  we  are  to  study  insects,  it  is  necessary  that  we  should  have  a 
clear  conception  of  just  what  an  insect  is  and  how  insects  may  be 
distinguished  from  other  animals.  Most  of  us  recognize  bees,  flies, 
beetles,  and  butterflies  as  insects,  but  other  forms  of  insect  life  we 


Fig.  I.    Earthworm 
w,  mouth  ;  c,  girdle,  or  clitellum.    (After  Jordan  and  Heath) 

should  probably  call  "worms,"  and  various  insectlike  animals  are 
commonly  termed  "  insects." 

The  animal  kingdom  is  divided  intoJtwo^large^rpups_of  animals, 
—  those  having  a  backbone,  the  Vertebrates,  and  those  without  a 
backbone,  the  Invertebrates.    In  the  former  are  included  all  the 


Fig.  2.    Diagram  to  express  the  fundamental  structure  of  an  arthropod 

a,  antenna ;  cil,  alimentary  canal ;  b,  brain  ;  d,  dorsal  vessel ;  ex,  exoskeleton  ;  /,  limb  ; 
;?,  nerve  chain  ;  s,  subesophageal  ganglion.  (After  Schmeil,  from  Folsom) 

higher  animals,  such  as  the  fishes,  reptiles,  birds,  and  mammals  ; 
while  in  the  latter  are  included  all  the  lower  forms  of  life,  vvhi^ 
are  usually  smaller  in  size  and  soft-bodied,  as  the  molluscs,  echino- 
derms,  worms,  insects,  and  their  relatives. 

^^'"  5 


6  ELEMENTARY  ENTOMOLOGY 

The  Invertebrata  are  divided  into  several  branches,  or  phyla  (sin- 
gular, phylum),  which  divisions  are  based  on  fundamental  differences 
in  the  body  structure  of  the  animals  in  these  groups.  Of  these 
phyla  there  are  two  which  have  the  body  made  up  of  a  series  of 
segments  and  were  at  one  time  classed  together  as  the  Articiilata. 


Fig.  3.    A  lobster;  a  typical  crustacean 

The  first  of  these  two  phyla,  the  Vermes,  or  worms,  has  no  jointed 
appendages,  while  the  second,  the  Arthropoda,  is  characterized  by 
having  jointed  appendages  on  either  several  or  all  segments  of  the 
body,  from  which  the  term  "Arthropoda,"  from  artJiron  (joint) 
and  pons  (foot),  is  derived.  The  Arthropoda  include  the  insects, 
spiders,  myriapods,  and  crustaceans,  all  of  which  are  related  by  the 
possession  of  these  jointed  appendages.    The  distinctions  between 


INSECTS  AND  THEIR  NEAR  RELA'l'IVES 


7 


these  four  classes  are  based  largely  upon  the  manner  in  which 
the  different  segments  are  grouped  together  to  form  compact  and 
distinct  parts  of  the  body,  and  b)-  the  number  and  position  of  the 
appendages. 

The  Crustacea  include  the  lobsters,  crabs,  crayfish,  shrimps,  bar- 
nacles, sow-bugs,  etc.,  and  are  primarily  distinguisTied  from  all  other 
arthropods  by_the_iactjhat  they  breathe  by  means  of  gills  and  live 
either  in  the  water  or  in  damp  places.  The  body  is  divided  into 
two  main  regions,  the 
anterior  segments  be- 
ing usually  covered  b)- 
a  single  large  shell 
forming  the  head-tho- 
rax, or  cephalothorax, 
while  the  remaining 
segments  form  the  ab- 
domen. Each  segment 
usually  bears  a  jpair  of 
appendages.  On  the 
head  are  found  two 
pairs  of  antennae,  and 
on  the  thorax  and  ab- 
domen are  numerous 
appendages  fitted  for 
walking  or  swimming. 

The  only  crustacean  commonly  mistaken  for  an  insect  is  the  little 
sow-bug,  or  pill-bug,  found  in  greenhouses,  under  boards,  or  in 
darhprpraces~7I^gr4y.  These  rarely  do  any  damage  and  may  be 
readily  distinguished  from  insects  by  the  two  pairs  of  antennae 
and  the  numerous  appendages.  The  gills  are  to  be  found  under 
plates  on  the  lower  side  of  the  abdomen. 

The  Arachnida  include  the  spiders,  scorpions,  ticks,  and  mites, 
and  are  almost  entirely  terrestrial.  The  body  is  divided  into  the 
cephalothorax  and  abdomen,  as  in  the  Crustacea,  but  there  are^o 
antennas  and  but  four  pairs  of  legs.  Although  ticliS-ajid  mites  are 
not  insects,  yet  they  are  so  nearly  related,  and  their  injuries  to  plants 
and  animals  are  so  similar  to  insect  depredations,  that  they  are  com- 
monl)'  included  in  economic  entomology.    Spiders  are,  if  anything, 


Fig.  4.    Sow-bug,  or  pill-bug    [Poirellis  laevis) 
Enlarged.    (After  Jordan  and  Heath) 


8 


ELEMENTARY  ENTOMOLOGY 


beneficial,  though  they  feed  on  beneficial  as  well  as  on  injurious 
insects,  while  scorpions  are  found  only  in  tropical  countries  and 

are  chiefly  a  nuisance  on  account 
of  their  poisonous  sting. 

The  Myriapoda  include  the  myri- 
apods  and  centipedes,  commonly 
called  thousa mi-legs.  Their  body 
consists  of  a  distinct  head  and  a 
long  abdomen,  all  of  the  segments 
of  which  are  similar,  and  each  of 
which  bears  a_j)air  of  legs,  so  that 
they  are  readily  distinguished  from 
all  other  arthropods.  In  many  ways 
the  myriapods  are  more  closely  re- 
lated to  the  insects  than  either  of 
the  other  classes  mentioned  above.  A  few  species  sometimes 
injure  vegetables  or  fruits  lying  on  or  in  the  ground,  and  these 
are  considered  as  within  the 
sphere  of  economic  entomol- 
ogy ;  but  for  the  most  part 
myriapods  are  harmless,  al- 
though the  house  centipede 


Fig.  5.    A  spider  ;  a  typical  arachnid 


Fig.  6.   A  myriapod 


Fig.  7.   A  parasitic  fly,  showing 
parts  of  a  typical  insect 

ant^  antennae  ;   h,  head  ;    /,  thorax  ; 
abd,  abdomen  ;  wg,  wings  ;  /,  legs 


is  a  nuisance  and  is  abhorred  by  the 
housekeeper.  Some  of  the  tropical 
myriapods  reach  relatively  enormous 
size,  being  several  inches  long,  and 
bear  poison  fangs  in  connection  with 
the  mouth-parts. 

The  Insecta,  or  Hexapoda,  include 
the  tme  insects,  which  form  the  largest 
group  of  animals  as  far  as  both  the 
number  of  different  species  and  the 
number  of  individuals  are  concerned. 
About  300,000  different  species  have 
already  been  described,  while  there  is 
probably  a  total  of  1,000,000  species 
in  existence.  The  known  species  form 
over  four  fifths  of  the  total  number  of 


INSECTS  AND  THEIR  NEAR  RELATIVES  9 

animals  now  described.  The  adult  insects  are  readily  recognized 
from  the  other  classes  of  arthropods,  but  many  of  the  immature 
forms,  such  as  maggots,  lack  the  typical  characteristics  of  the 
group.  The  segments  of  the  body  of  an  insect  are  grouped  into 
three  distinct  regions,  —  thejiead,  the  thorax,  and  the  abdomen, 
The  liead  bears  a  single  pair  of  feelers,  or  antenn^,  the  mouth-parts, 
and  the  conipound  eye^s.  The  thorax  bears  three  pairs  of  jointed 
legs  and  in  the  adult  stage  usually  two  pairs  of  wings,  though  in 
the  flies  there  is  but  a  single  pair  and  in  a  few  orders  wings  are 
lacking.  The  abdomen  is  usually  without  appendages  in  the  adult 
state,  although  on  caterpillars  and  other  immature  stages  prolegs, 
or  false  legs,  which  are  not  segmented,  are  often  found. 

Comparative  Structure  of  the  Classes  of  Arthropoda 


Class 

Parts  of 

Body 

AnTENN/E 

Eyes 

Legs 

in,>ge,/ 

I              2 

3 

Insecta 

Head,  thorax, 

abdomen 

One  pair 

Compound 

Six 

JJ7/tgA-ss 
Myriapoda 

I 
Head, 

abdomen 

One  pair 

Compound 

One  pair  per 
segment 

Arachnida 

Head-thorax, 

abdomen 

None 

Simple 

Eight 

Aquatic 

I 

2 

Crustacea 

Head-thorax, 

abdomen 

Two  pairs 

Compound 

Many 

CHAPTER  III 

ANATOMY  OF  INSECTS  —  EXTERNAL 

Body  structure.  The  extinct  ancestors  of  the  insects  were 
doubtless  elongate,  wormlike  animals  composed  of  a  series  of 
cylindrical  segments  very  similar  in  structure  and  with  a  pair  of 
jointed  appendages  attached  to  each  segment.    The  mouth  being 


Fig.  8.    Types  of  insect  antennae 

A,  filiform,  from  grasshopper  {Schisfoccrca  amcrkana)  ;  i?,  clubbed,  or  clavate,  from  teneb- 

rionid  beetle  i^Nyctobaics  pcnnsykaiilcus)  ;  C",  pectinate,  or  feathered,  from  a  moth  ;  Z*,  aris- 

tate,  with  dorsal  plumose  arista,  from  a  fly ;  E^  lamellate,  from  a  May-beetle  {Lac/mosiema 

fiisca)  ;  F,  moniliform,  from  a  beetle 

at  the  anterior  end,  the  appendages  near  it  were  developed  to 
secure  and  tear  up  the  food.  Thus  the  mouth-parts  were  gradu- 
ally evolved,  and  the  segments  bearing  them  grew  closer  together 
until  they  coalesced  and  formed  a  single  well-defined  region,  the 
head.  With  the  development  of  wings  the  appendages  of  the  pos- 
terior segments  were  useless  and  soon  disappeared,  and  the  legs 
on  the  three   segments   immediately  back  of  the  head   became 


ANATOMY  OF  INSECTS  —  EXTERNAL 


II 


further  specialized  as  organs  of  locomotion.  With  the  development 
of  the  large  muscles  necessary  for  the  propulsion  of  the  wings  and 
legs,  these  three  segments  back  of  the  head  became  sharply  differ- 
entiated from  the  rest,  so  that  they  now  form  a  quite  distinct 
region,  the  thorax.  The  remaining  posterior  segments,  called  the 
abdomoi,  having  lost  most  of  their  appendages,  are  quite  similar 
in  form,  with  the  exception  of  those  at  the  extreme  posterior  end, 
where  the  shape  of  the  segments  and  of  their  appendages  has 
been  modified  in  connection  with  the  external  sexual  organs.  The 
insect  is  therefore  divided  into  three  well-defined  parts,  —  the  head, 
the  thorax,  and  the  abdomen,  —  which  are  composed  of  more  or 
less  visible  segments. 

The  head.  The  embiyolog}^ 
and  nervous  system  of  the  head 
show  that  it  was  originally  com- 
posed of  six  segments,  almost 
no  traces  of  which  are  now 
discernible  except  their  append- 
ages, of  which  four  pairs  are  rec- 
ognizable as  homologous  with 
the  thoracic  legs  and  the  ab- 
dominal appendages  of  lower 
forms.  These  appendages  con- 
sist of  the  feelers,  or  antennas, 
and  three  pairs  of  mouth-parts. 
The  head  also  bears  a  pair  of 
compound  eyes  and  often  a  variable  number  of  simple  eyes,  or  ocelli. 

Antennae.  The  antennae  are  often  called  feelers,  indicating  their 
principal  function  as  sense  organs,  which  will  be  discussed  in  con- 
sidering the  senses.  The  shape  of  the  antennae  is  very  different 
in  different  groups  of  insects,  as  is  also  the  number  of  segments, 
both  of  which  characters  are  of  the  greatest  importance  in  dis- 
tinguishing the  various  groups.  In  the  case  of  the  katydid  the 
threadlike  antennas  are  much  longer  than  the  body,  while  in  some 
flies  they  are  reduced  to  mere  knobs  with  a  single  strong  bristle. 
The  different  shapes  of  the  segments  give  rise  to  many  different 
characteristic  types  of  antennae,  some  of  the  more  important  of 
which  are  shown  in  Fig.  8.    In  many  cases,  notably  in  the  moths 


'^^J 


Fig.  9.    Head  of  drone  bee,  showing 
compound  and  simple  eyes 

(After  A.  B.  Comstock) 


12 


ELEMENTARY  ENTOMOLOGY 


and  mosquitoes,  the  antennae  of  the  sexes  are  quite  different,  so 
that  the  sexes  are  readily  distinguishable. 

Eyes.  On  either  side  of  the  antennae  are  found  the  large  com- 
pound eyes,  often  forming  the  larger  part  of  the  side  of  the  head, 
and  sometimes,  as  in  the  dragon-fly  and  horse-fly,  forming  the 
major  portion  of  the  head.  .  The  compound  eyes  are  usually  oval 
or  circular  in  outline,  and  are  called  compound  because,  when 
examined  under  a  lens,  they  are  seen  to  be  composed  of  large 
numbers  of  hexagonal  areas,  called  facets.  The  number  of  these 
facets  varies  from  50  in  certain  ants  to  4000  in  the  house-fly  and 


-mx.p 


lab 


^Ib.p 


Fig.  10.    Face  of  grasshopper 

an/,  antenna  ;  f/,iclypeus  ;  eye,  compound  eye  ;  /ad,  labium  ;  //>r,  labium  ;  /l>./,  labial  palpi ; 
""^ mx./,  maxillary  palpi ;  oc,  ocellus 

27,000  in  certain  sphinx  moths.  Between  the  compound  eyes, 
on  the  front,  or  vertex,  of  the  head,  are  two  or  three  small  oval 
or  circular  simjple^  eyes^-Calied^^^-///.  Caterpillars  and  other  larvae 
have  no  compound  eyes,  but  on  either  side  of  the  head  have  a 
group  of  from  four  to  six  ocelli.  In  many  flies  and  bees  the  com- 
pound eyes  of  the  male  are  larger  and  closer  together  than  those 
of  the  female,  this  being  due,  possibly,  to  the  male's  leading  a 
more  active  life. 

Mouth-parts.  The  mouth-parts  are  of  prime  importance,  both 
from  an  economic  and  from  a  systematic  standpoint.  Upon  their 
structure  depends  the  kind  of  insecticide  which  may  be  effectively 


ANATOMY  OF  INSECTS  —  EXTERNAL 


13 


used,  and  their  structure  is  so  constant  and  characteristic  in  different 
groups  as  to  furnish  one  of  the  best  meansjaf  classification.  Most 
of  the  orders  possess 
one  of  the  two  main 
types  of  mouth-parts, 
—  those  formed  for 
biting  (mandibulate), 
and  those  formed  for 
sucking  (suctorial,  or 
haustellate).  The  bit- 
ing type,  as  found  in 
the  grasshopper,  is  the 
more  typical,  and  will 
therefore  be  discussed 
first. 

The  labr?nii,  or  up- 
pei^Jip,  is  a  simple 
flap  projecting  over 
the  upper  part  of  the 
opening  of  the  mouth 
and  cover in^gjlifr-Hian- 
dibles.  It  is  hingsd-On 
the  posterior  margin,  but  otherwise  is  free  and  may  be  slightly 
protruded  01^ retracted,  to  aid  in  bringing  food  to  the  mandibles. 


Fig.  II.    Mouth-parts  of  grasshopper,  typical  biting 
or  mandibulate  mouth-parts 

//'r,  labrum,  or  upper  lip  ;  md,  mandible  ;  wx,  maxilla  ;  hil>, 

labium,  or  lower  lip  ;  /,  palpus  ;  g,  galea ;  /,  lacinia  ;  lig, 

ligula  ;  hyp,  hypopharyn.x 


Fig.  12.   Various  forms  of  mandibles 

A,  grasshopper  {Melanopbts)  ;  B,  tiger  beetle  (Cicindcfulae)  ;  T,  bee  {Apis)  ■' D,  Onthopha- 
gus  ;  E,  lace-winged  fly  {Chrysopd)  ;  F-I,  soldier  termites.    (After  Hagen,  from  Folsom) 


The  majtdibles,  or  jaws,  are  composed  of  a  single  toothlike 
piece  and  move  in  a  transverse  plane.    The  form  of  the  mandibles 


14 


PILEMKNTARY  ENTOMOLOGY 


is  modified  according  to  the  food  of  the  insect.  Thus,  in  the  grass- 
hopper and  similar  insects  feeding  upon  vegetation  the  mandibles 
are  short,  with  strong  teeth  at  the  tip  and  behind  them  a  crushing 
or  grinding  surface.  In  carnivorous  and  pre- 
daciou§>insects  the  mandibles  are  usually 
long,  slender,  and  sharply  toothed,  adapted 
for  grasping  the  prey  or  tearing  flesh.  In 
certain  of  the  Neuroptera,  as  in  the  aphis- 
lion  (see  page  92),  the  mandible  has  a 
deep  groove  on  the  inner  surface,  through 
which  the  juices  of  the  plant-lice  are  sucked. 
In  soldier  ants  the  mandibles  are  developed 
as  effective  weapons,  while  in  other  forms 
they  are  otherwise  specialized  according  to 
the  food  habits  of  the  insect ;  but  they  are 
always  essentially  biting  organs. 

Beneath  the  mandibles  are  the  maxillce,  or 
under  jaws.  The 
maxillae  are  much 
more  complex,  con- 
sisting of  a  basal 
portion  (stipes) 
which  is  hinged  to 
the  head  (by  the 
cardo)  and  which 
the  palpus,  galea, 
and  lacinia.  The  palpus  is  composed 
of  four  or  five  segments,  resembles  a 
miniature  antenna,  and,  like  it,  is  a 
sensory  organ.  The  inner  lobes,  the 
lacinia,  are  usually  provided  with  teeth 
or  spines  and  aid  the  mandibles  in  hold- 
ing and  masticating  the  food. 

The   third   pair  of  mouth-parts  have 
grown  together  on  the  median  line  so  as 
to  form  a  single  piece,   known  as   the 
labinni,  or  underlip.    In  the  embryo  this  is  composed  of  a  pair  of 
appendages  similar  to  the  maxillae,  and  for  this  reason  is  sometimes 


Fig.  13.     Maxilla  of  a 
ground  beetle   {Harpa- 
lits  i-ciliginosus),  ventral 
aspect 

c,  cardo ;    g,  galea ;   /,  la- 
cinia ;  /,  palpus  ;  //,  palpi- 
fer;  s,  stipes  ;  sg,  subgalea 
(After  Folsom) 

bears  three  lobes,  - 


Fig.  14.   Labium  of  a  ground 

beetle  [Harpaliis  caliginosits), 

ventral  aspect 

g,  united  glossas,  termed  the  glos- 
sa ;  ;«,  mentum ;  /,  palpus ;  fg^ 
palpiger;  /;•,  paraglossa  ;  sm,  sub- 
mentum.  The  median  portion  of 
the  labium  beyond  the  mentum  is 
termed  the  ligula.  (After  Folsom) 


ANATOMY  OK  INSECTS  —  EXTERNAL 


15 


termed  the  second  tnaxillce.  The  labium  forms  the  floor  of  the 
mouth  and  assists  the  mandibles  and  maxillas  with  the  food.  It  is 
hinged  to  the  head  at  its  base  (by  the  viejitjivi\,  and  projecting 
from  either  side  is  a  palpjis,  similar  in  form  and  function  to  the 
maxijlary  palpi.  Between  the  palpi  are  one  or  two  pairs  of  lobes, 
the  ligiila. 

""Projecting  into  the  cavity  of  the  mouth  from  the  inner  sur- 
face of  the  labium  is  the  hypopharynx\  or  tongue.    This  in  the 


Fig.  15.    Mouth-parts  of  the  squash-bug 

lab^  labium,  forming  a  sheath  for  the  other  parts  ; 
Ibr^  labrum,  fitting  into  the  lower  part  of  the 
suture  of  the  labium  ;  nni,  mandible  ;  w.v,  max- 
illa.  Mandibles  and  maxillee  pulled  out  of  labium 


Fig.  16.  Side  view  of  head 

of     butterfly,     with     part 

of   antennae    {a)   removed, 

showing  mouth-parts 

w.v,  maxillae  ;  /,  labial  palpus 


grasshopper  is  a  fleshy,  tonguelike  organ,  but  in  some  orders  it 
is  quite  differently  developed.  The  salivary  glands  open  near  its 
attachment. 

Suctorial  type  of  mouth-parts.  The  mandibulate  mouth-parts 
of  the  different  orders  are  all  of  so  similar  a  type  as  to  be  appar- 
ently homologous.    The  suctorial  mouth-parts  consist  of  several 


i6 


ELEMENTARY  ENTOMOLOGY 


very  distinct  types,  entirely  dissimilar  in  structure  and  origin, 
resembling  each  other  only  in  that  they  enable  the  insect  to  suck 
or  lap  its  food  rather  than  to  bite  it. 


Fig.  17.    Cross  section  of  proboscis  of  cotton-worm  moth,  showing  concave  inner 

faces  of  maxillae  locked  together  to  form  the  sucking  tube 

(After  Comstock) 


,.  „,    '    ''■  ''     » 


Fig.  18.    Mouth-parts  of  female  mosquito  {Ciihx pipiens) 

A,  dorsal  aspect;  B,  transverse  section;  C,  tip  of  maxilla;    Z),  tip  of  labrum-epipharynx ; 

(T,  antenna ;    c,  compound  eye ;    //,  hypopharynx ;    /,  labrum-epipharynx ;   A,  labium ;   mx, 

maxilla  ;  w,  mandible  ;  /,  maxillary  palpus,    (After  Folsom  and  Dimock) 


ANATOMY  OF  INSECTS  —  EXTERNAL 


17 


Hemiptera.  In  the  Hemiptera,  or  bugs,  the  labium  forms  a  long, 
jointed  beak,  or  rostrum  (Fig.  15).  This  rostrum  is  cylindrical  in 
section,  and  its  evolution  from  the  type  of  labium  found  in  the  grass- 
hopper may  be  understood  by  conceiving  the  labium  of  the  latter 
to  be  greatly  elongated  and  then  curled  up  on  either  side  until  the 
lateral  margins  meet 
on  the  median  line 
above,  forming  a  su- 
ture, as  seen  in  the 
hemipterous  beak.  At 
the  base  of  this  suture 
is  found  a  triangular  la- 
brum  closing  the  base 
of  the  tube.  The  man- 
dibles and  maxillae  are 
long,  .  bristlelike  or 
needlelike  structures, 
sharply  pointed  and 
often  bearing  barbs  at 
the  tip,  and  the  max- 
illae are  locked  to- 
gether so  as  to  form  a 
tube^  through  which 
the  juices  are  sucked. 

Lepidoptera.  The 
moths  ^nd  butterflies 
possess  a  ver}'  different 
style  of  sucking  tube, 
or  proboscis,  which  is 
curled  up  under  the  head  like  a  watch  spring.  This  is  composed 
of  the  two  maxillae,  whose  inner  faces  are  concave  and  which  lock 
together  so  as  to  form  a  tube  which  opens  into  tlie  moufh.  All 
the  other  mouth-parts  are  almost  entirely  absent  in  most  forms, 
except  the  labial  palpi.  It  is  evident  that  this  type  of  mouth-part  is 
only  adapted  to  sucking  nectar  from  flowers  and  is  never  injurious 
to  vegetation,  while  often  adapted  for  pollenizing  flowers  which  the 
moths  frequent.  The  caterpillars  of  moths  and  butterflies  have 
biting  mouth-parts  similar  to  those  of  the  grasshopper. 


Fig.  19.    Side  view  of  head  of  a  fly 
«,  antenna  ;  wa/,  maxillary  palpus  ;  Ar/',  labellum 


i8 


ELEMENTARY  ENTOMOLOGY 


Diptera.  The  flies  have  several  types  of  mouth-parts,  all  essen- 
tially suctorial.  Those  of  the  horse-fly  and  mosquito  are  good 
examples  of  the  piercing  type  (Figs.  15,  18,  20).  Superficially  they 
resemble  those  of  the  Hemiptera,  but  the  sheath  of  the  beak  is  not 
so  strong  and  is  quite  open  above,  and  there  are  six  lancetlike  or- 
gans which  in  the  horse-fly 
are  quite  strongly  devel- 
oped. The  esophagus  is 
controlled  by  sets  of  mus- 
cles which  make  it  an  effec- 
tive bulb  for  pumping  up 
the  food.  The  common 
house-flies  and  blow-flies 
have  mouth-parts  (Fig.  1 9) 
adapted  for  rasping  or  lap- 
ping rather  than  for  pierc- 
ing, though  the  liquid  food 
is  sucked  up  in  much  the 
same  way.  The  proboscis 
consists  principally  of  the 
very  complex  labium,  or 
lower  lip,  which  is  very 
much  expanded  at  the  tip 
to  form  a  pair  of  fleshy 
lobes.  When  looked  at 
under  the  microscope,  the 
tip  of  the  proboscis  is 
seen  to  contain  a  series 
of  grooves  and  transverse 
horny  ridges  with  sharp, 
projecting  edges.  With 
these  rasplike  projections  the  fly  is  enabled  to  scrape  the  surface 
of  the  food  and  gradually  loosen  small  particles,  which  are  dissolved 
or  carried  in  the  saliva  to  the  mouth. 

Hymenoptera.  The  mouth-parts  of  the  Hymenoptera  include 
both  biting  and  sucking  types.  The  saw-flies  and  ants  (Fig.  22) 
have  well-developed  biting  mouth-parts,  which  are  used  as  such, 
while  in  the  wasps  and  bees  the  maxillae  and  labium  form  a  tube 


Fig.  20.    Mouth-parts  of  horse-fly  {Tahantis) 

Upper  figure  showing  mouth-parts  separated,  and 

lower  figure  showing  lancets  dissected  out.    (After 

J.  B.  Smith) 


ANATOMY  OF  INSECTS  —  EXTERNAL 


19 


around  the  greatly  elongated  tongue  (hypopharynx)  which  is  used 
for  lapping  and  sucking,  though  the  mandibles  are  still  functional 
and  are  used  in  shaping  wax  and  pollen. 

It  should  be  noted  that  in  several  of  these  orders  having  suctorial 
mouth-parts  in  the  adult  stage  the  larvae  have  true  biting  mouth- 
parts.    Caterpillars  of  all  the  Lepidoptera  and  the  larvae  of  many 


Fig.  21.    Mouth-parts  of  the  honey-bee 

a,  antenna ;  /,  labellum  ;  g,  glossa,  or  tongue  ;  bn,  labrum  ;  Ip^  labial  palpi ;  m,  mandible  ; 
)«.v,  maxilla  ;  mxp,  maxillary  palpus  ;  pg,  paraglossa 

families  of  flies  and  Hymenoptera  have  biting  mouth-parts  and  are 
injurious  to  vegetation,  while  the  adults  may  be  entirely  harmless. 
This  difference  in  the  mouth-parts  of  the  same  insect  in  different 
stages  must  be  borne  in  mind  in  considering  insecticides  for  them. 


20 


ELEMENTARY  ENTOMOLOGY 


We  have  stated  that  the  structure  of  insects  often  determines 
the  method  of  treating  them.    This  may  now  be  understood,  for 

it  is  evident  that 
./  a  poison   such  as 

Paris  green,  ap- 
phed  to  the  food 
of  a  sucking  in- 
sect, such  as  a 
plant-louse,  would 
not  be  taken  into 
the  mouth  through 
the  sucking  mouth- 
parts,  which  ex- 
tract only  the  juices 
beneath  the  sur- 
face, while  it  might 
be  entirely  effect- 
ive against  an 
insect  with  biting 
mouth-parts,  which 
consumed  the  sur- 
face covered  by  the 
poison.  A  better 
understanding  of 
these  simple  facts 
of  insect  anatomy 
would  save  Amer- 
ican farmers  thou- 
sands of  dollars 
every  year,  now  lost 
through  ignorance. 
Thorax.  The  thorax  is  the  middle  region  of  the  body,  composed 
of  the  three  segments  back  of  the  head,  which  are  called  the  ^ro- 
tJiorax^  mesothoi-ax,  and  nietathorax  respectively.  As  previously 
indicated,  the  differentiation  of  the  thorax  has  been  incidental  to 
the  development  of  the  wings,  and  the  structure  of  the  thorax  is 
determined  by  the  development  and  use  of  the  organs  of  locomo- 
tion.   A   pair  of  jointed   legs   is  attached  to  each  segment  and 


Fig.  22.    Mouth-parts  of  an  ant  {Mymiica  ntl>?-a) 

A,  seen  from  the  lower  side  in  siiti ;  B  and  Z>,  maxillae; 
C,  labium  seen  from  the  upper  side,  detached ;  a,  mandible  ; 
h^  maxilla ;  f,  mentum  ;  d,  maxillary  palp  ;  e,  labial  palp  ;  /, 
glossa  or  tongue ;  g,  adductor  muscle  of  mandible  ;  h,  abductor 
muscle  of  mandible ;  /',  labium  ;  k,  gustatory  organs ;  /,  duct 
of  salivary  glands ;  ;«,  maxillary  comb :  «,  gular  apodeme. 
(After  Janet,  from  Wheeler) 


ANATOMY  OF  INSECTS  —  EXTERNAL 


21 


the  mesothorax  and 
metathorax  of  most 
adult  insects  bear  a 
pair  of  wings.  The 
prothorax  is  usually 
smaller  than  the 
two  posterior  seg- 
ments, the  relative 
size  of  which  de- 
pends upon  which 
pair  of  wings  is  the 
better  developed. 
The  dorsal  surface, 
or  back,  of  a  tho- 
racic segment  is 
called  the  tergmn, 
or  notinn,  the  ven- 
tral or  under  sur- 
face is  the  sternum, 
and  each  side  is 
a  plcurum.  These 
parts  are  further 
divided  by  sutures 
into  distinct  plates, 
or  sclcritcs,  to  which 
the  appendages  are 
articulated.  The  de- 
velopment, shape, 
size,  and  position  of 
these  sclerites  are 
characters  of  such 
uniformity  that  the 
sclerites  are  used 
in  classifying  in- 
sects, in  much  the 
same  way  as  are 
the  bones  of  the 
vertebrate  animals. 


22 


ELEMENTARY  ENTOMOLOGY 


i-Cla 


Fig.  24.   Typical  insect  leg 


Cx,  coxa  ;  C/a,  claws  ;  Ji'it/,  empodia  ;  /%  femur  ;    Tar,  tarsal 

segments ;     Tl>,  tibia ;     Tr,    trochanter,     (.\fter   Snodgrass, 

United  States  Department  of  .Agriculture) 


Legs.  The  legs  articulate  with  the  sternum  and  pleurum  and  con- 
sist of  five  parts,  —  the  coxa,  (ror/iajjtfj;  fcitiuj:.  tibia,  and  iarsj/s. 
The  hase  of  the  coxa  forms  the  joint  of  the  leg  to  the  bod^',  which 

is  either  of  the  ball- 
and-socket  or  of  the 
hinge  type.  The  tro- 
chanter is  a  small,  in- 
termediate segment, 
which  in  parasitic  Hy- 
menoptera  is  double. 
The  femur  is  the 
largest  segment  in 
the  leg,  and  in  grass- 
hoppers and  other 
jumping  insects  is 
strongly  developed 
by  the  muscles  with- 
in. The  tibia  is_  usu- 
ally long  and  slender.  The  tarsus  is  usually  composed  of  several 
similar  segments,  five  being  the  typical  number.  The  last  segment 
usually  bears  a  ^ir  of  sharp  claws  in  adult  insects  and  a  single 
claw  in  larvae.  Between  the  claws  of  most  adult  insects  is  a  little 
pad,  called  a  pnlvillns,  or  cmpodinm,  a  suckerlike  organ  which 
enables  them  to  walk  upon  smooth  surfaces  and  to  cling  to  objects 
when  upside  down. 

Nearly  all  adult  and  most  larval  insects  have  three  pairs  of 
thoracic  legs,  but  many  boring  and  parasitic  larvae  have  lost  them 
entirely.  The  legs  are  often  greatly  modified  according  to  the  habits 
of  the  insect,  not  only  for  locomotion,  but  for  grasping,  digging,  and 
other  purposes.  The  legs  of  most  beetles  are  typical  of  walking 
insects.  In  jumping  insects,  like  the  grasshopper  and  flea  beetles, 
the  hind  femora ^re  greatly  developed.  In  diggingjnsects,  such  as 
the  mole  cricket  and  cicada  nymphs,  the  tibia  "and  tarsus  of  the  fore- 
legs are  developed  as  shovels.  The  forelegs  of  many  predacious 
insects,  such  as  the  mantis,  assassin  bugs,  and  others,  bear  teeth 
upon  the  opposing  surfaces  of  the  tibia  and  femur,  which  make 
them  efficient  grasping  organs.  The  legs  of  the  bees  are  highly 
developed  :  the  forelegs  bear  a  comb  for  cleaning  the  antennae, 


ANATOMY  OF  INSECTS  —  EXTERNAL 


the  metatarsi  bear  a  series  of  spines  used  as  a  pollen  comb,  and 
the  metatibiae  bear  a  fringe  of  hairs  on  the  outer  surface  surround- 
ing what  is  called  the  pollen  basket,  adapted  for  carr)dng  pollen. 


Fig.  25.    Types  of  insect  legs 

A,  grasshopper  {ScMstocerca  ama-icmia)  ;  B,  a  cicindelid  beetle  {Cichtdela  b-guiiata)  ;  C.  a 
gyrinid  beetle  {Dincntcs  vitlatiis)  ;  Z),  ayoung  mantis  ;  E,  a  mole  cricket  {G)yllotalpa  borcalis) 

In  aquatic  forms  the  legs  are  variously  developed  for  swimming  or 
skimming  over  the  surface.  The  males  frequently  have  the  fore- 
legs developed  for  grasping  the  females,  as  in  the  suckerlike  disks 
on  the  fore  tarsi  of  the  predacious  diving  beetles  {Dytiscidac).  In 
general,  insects  which  are  strong  fliers  and  are  usually  on  the  wing 
have  weak  legs. 

Wings.    Millions  of  years  ago  insects  became  the  pioneers  in 
aerial  navigation  by  the  development  of  wings,  which  have  un- 
doubtedly been  chiefly  responsible  for  the  enormous  development 
of  insects  as  a  class,  living  in 
all  latitudes  and  environments. 
The  largest  existing  insects  are 
certain  tropical    moths  whose 
wings    expand    nearly  a   foot, 
but  fossils  from  the  coal  age 
show  that  immense  phasmids 
(nearly  related  to  grasshoppers) 
then  existed,  with  a  wing  ex- 
panse of  over  two  feet.    The 

largest  wings  are  not,  however,  always  the  most  serviceable,  and 
the  strongest  fliers  are  usually  of  medium  size.  ThejwingS-PE£- 
sent  a  variation  of  structure  in  almost  every  group,  and,  with  the 


.fiADlVS 


Fig.  26.    Hypothetical  type  of  wing 
venation 

(Adapted  from  Comstock  and  Needham) 


24 


ELEMENTARY  ENTOMOLOGY 


mouth-parts,  form  the  most  important  basis  for  classification.  Thus 
most  of  the  orders  are  distinguished  by  differences  in  the  wings,  as 
indicated  by  their  names,  which  usually  end  in  -ptera  (from  pteron, 
a  wing),  and  many  insects  may  be  classified  to  the  genus  or  even  to 
the  species  by  the  wings  alone,  this  being  particularly  true  of  fossil 
forms,  in  which  the  wings  are  often  the  only  parts  well  preserved. 
Most  adult  insects  possesstwo  pairs  of  wings,  borne  by  the  meso- 
thorax  and  metathorax,  but  in  some  parasitic  orders  the  wings  have 
been  lost,  and  one  order,  the  Thysanura,  represents  the  primitive 
insect  without  wings.  In  the  flies  (Diptera)  only  the  mesothoracic 
wings  are  developed^,  and  the  metathoracic  wings  are  represented  by 
clublike  appendages,  called  Jialtcrcs,  or  balancers.  The  relative  shape 

and  size  of  the  two  pairs  vary 
greatly,  and  frequently  the 
two  wings  of  each  side  over- 
lap or  are  held  together  by 
various  structures,  so  that 
they  act  as  a  single  organ. 
The  wings  are  strengthened 
by  numerous  thickenings, 
called  veins,  whose  number 
and  position  form  the  basis  of 
the  classification  of  families, 
genera,  and  species.  It  has 
been  shown  by  Professors  Comstock  and  Needham  that  the  prin- 
cipal veins  are  homologous  in  all  the  orders  of  insects,  and  that 
they  have  been  derived  from  one  original  type,  either  by  the  disap- 
pearance of  certain  veins,  by  their  growing  together,  or  by  the 
addition  of  supplementary  veins.  The  typical  longitudinal  veins,  as 
shown  in  Fig.  26,  are  the  casta,  subcosta,  radius,  media,  cubittis, 
and  anals.  The  costa  (r)  is  unbranched  and  strengthens  the 
anterior  margin  of  the  wing.  The  subcosta  {se)  is  typically  two- 
branched,  though  often  single,  and,  where  the  costa  is  small  or 
wanting,  appears  to  be  the  first,  or  anterior,  vein.  The  radius  (;-)  is 
typically  five-branched,  the  base  of  the  second  principal  branch, 
from  which  the  four  posterior  branches  divide,  being  known  as  the 
radial  sector.  The  media  («/)  is  typically  four-branched,  though 
often  but  two  or  three  branches  are  present.     Cubitus  (r^)Jias 


Fig.  27.   Wing  of  house-fly  [Musca  dotnesii- 

ca),  showing  speciaUzation  of  wing  venation 

through  reduction  of  veins 


c,  costa ;   r, 


radius ;    m,  media  ;    at,  cubitus  ; 
anal.    (After  Comstock) 


ANATOMY  OF  INSECTS  —  EXTERNAL 


25 


usually  two  branches.  The  anal  veins  (a)  are  typically  three  in, 
number,  but  often  one  or  two  are  lost,  and  in  other  groups  the 
anal  area  is  greatly  expanded  and  they  become  many-branched. 
Specialization  by  reduction  in  the  number  of  veins  is  seen  in  the 
wings  of  the  flies,  bees,  and  butterflies  and  moths,  while  special- 
ization by  addition  is  found  in  the  wings  of  Orthoptera  and  the 
neuropterous  orders. 

In  several  orders  the  front  wings  are  modified  to  form  wing- 
covers  for  the  hind  wings  and  are  not  used  in  flight.  Thus  the 
front  wings  of  the  beetles,  called  elytra,  are  hard  and  horny,  those  of 
the  grasshoppers  are 
leathery,  and  those 
of  the  bugs  are  leath- 
ery  at  the  base,  with 
membranous  tips. 

In  addition  to  be- 
ing^qrgans  of  flight, 
the  wings  sometimes 
have  other  functions. 
T-hus  in  crickets  and 
other  Orthoptera  the 
wings  bear  sound- 
producing  structures, 
and  the  honey-bee 
maintains  the  temperature  of  its  hive  by  the  body  heat  derived 
from  the  incessant  motion  of  the  wmgs. 

Abdomen.  The  ten  segments  of  the  abdomen  are  the  most  dis- 
tinct and  simple  of  the  body.  The  jointed  appendages  have  been 
almost  entirely  lost  in  adult  insects,  and  the  abdomen  merely  houses 
the  respiratory,  digestive,  and  genital  systems,  the  posterior  seg- 
ments being  modified  in  connection  with  the  external  sexual  organs. 
In  the  lowest  order,  the  Thysanura,  rudimentary  abdominal  append- 
ages still  exist,  and  caterpillars  and  other  larvae  frequently  bear 
several  pairs  of  fleshy,  unsegmented  prolegs,  or  false  legs,  bearing 
a  circlet  of  hooks  at  the  tip.  In  several  orders  the  "females  bear  an 
ovipositor,  or  ^-gg  guide,  which  has  been  developed  from  a  speciali- 
zation of  the  appendages  of  the  seventh,  eighth,  and  ninth  seg- 
ments.  The  females  of  many  grasshoppers  and  crickets  bear  large 


28.   ^\  ing  of  May-fly,  showing  specialization  of 
wing  venation  by  addition  of  wing  veins 

Lettering  as  in  Fig.  27.    (After  Folsom) 


26 


ELEMENTARY  ENTOMOLOGY 


ovipositors,  with  which  they  are  enabled  to  insert  their  eggs  in  the 
ground  or  in  wood,  but  the  greatest  development  of  the  ovipositor 
is  found  among  hymenopterous  insects  in  which  it  is  formed  for 
sawing,  boring,  or  stinging.    Another  pair  of  jointed  appendages, 


Fig.  29.    Ovipositor  of  periodical  cicada 
At  rest  at  .A,  and  exserted  at  B 


—  C^ 


called  ccfci,  are  frequently  found  attached  to  the  tenth  abdominal 
segment.  They  are  quite  variable  in  length,  but  in  May-flies  are 
as  long  as  the  body  and  resemble  very  slender  antennae  projecting 
backward  from  the  abdomen.    In  most  cases  they  are  tactile  organs, 

but  in  the  cockroach  they  assist  in 
smelling. 

The  nurnber  of  visible  abdom- 
inal segments  varies  from  five  .to 
eleven  in  different  orders,  and  fre- 
quently the  number  is  different  on 
the  upper,  or  dorsal,  and  under,j3r 
ventral,  sides.  The  structure  of- the 
anal  segments  is  usually  different 
in  the  sexes  and  furnishes  impor- 
tant characters  for  classificatioru  - 

Integument.      Before    studying 
the  internal  anatomy,  the  skin,  or 
integument,   of  the  insect  should 
be  considered.    This  has  become 
hardened  so  that  it  forms  a  firm  outer  skeleton,  to  which  the  mus- 
cles and  internal  organs  are  attached.  Thus  the  parts  of  the  insect 
skin,  as  have  been  described,  are  analogous  to  the  bony  skeleton 


Fig.  30.    Section  tlirough  skin  of  a 
beetle  {Chrysobothris) 

b,  basement  membrane  ;  c',  primary  cutic- 

ula  ;  C-,  secondary  cuticula  ;  //,  hypoder- 

mis  cell ;  ;?,  nucleus,   (.'\fter  Tower,  from 

Folsom) 


ANATOMY  OF  INSECTS  —  EXTERNAL 


27 


of  higher  animals  in  that  they  support  the  tissues  of  the  body^  and 
their  structure  is  characteristic  of  the  different  groups.  This  ha_rd- 
ening  of  the  skin  is  found  in  all  arthropods  and  is  due  to  a  sub- 
stance, called  cJiitin,  which  is  formed  by  the  lower  layer  of  cells  of 
tliL'  sl^in,  the  hypodermis,  and  which  forms  an  impervious,  hard 
la\cr  o\cr  the  body  of  the  entire  animal,  though  but  slightly  devel- 
oped in  the  membranous  joints  between  the  segments.  Chemically, 
chitin  is  somewhat  akin  to  silk,  or  to  the  spongin  of  the  sponge  skele- 
ton. It  is  unaffected  by  ordinary  acids  and  alkahes,  though  soluble 
in  sodic  or  potassic  hypochlorite.  The  insolubility  of  chitin  is  of 
impoi'tance  in  the  consideration  of  insecticides,  for  there  is  hardly 
anything  that  can  be  applied  to  any  but  the  most  soft-bodied  insects 
which  will  corrode  the  skin  without  injuring  the  foliage  of  the 
plants  upon  which  they  feed.  The  surface  of  the  chitinous  skin 
may  be  smooth  or  pitted,  wrinkled,  striated,  granulated,  or  marked 
in  various  characteristic  ways.  The  chitin  is  not  only  developed 
by  the  outer  skin  but  is  formed  on  the  surface  of  the  entire  epider- 
mis, including  the  lining  of  the  anterior  part  of  the  alimentary  tract 
and  the  respiratory  tubes,  or  trachea,  as  can  be  seen  by  the  exam- 
ination of  a  cast  skin  after  an  insect  has  molted. 


CHAPTER   IV 

ANATOMY  OF  INSECTS  —  INTERNAL 

The  general  arrangement  of  the  internal  organs  of  an  insect 
may  be  understood  by  a  study  of  transverse  and  longitudinal  sec- 
tions, as  shown  in  Figs.  31  and  32.    Attached  to  the  inside  of 


Fig.  31.    Ideal  section  through  an  insect 

a,  alimentan-  canal ;  //,  heart ;  «,  nerve  cord  ;  s,  stigmata,  or  spiracles  :  /,  tracheal  tubes  ; 
/,  legs;  7c,  wings.    (From  Riverside  Natural  Historj) 

the  body  wall  are  found  layers  of  longitudinal  and  vertical  mus- 
cles which  control  the  body  movements.  Through  the  center  of 
the  body  runs  a  large  tube,  the  alimentary  canal,  or  digestive  tract. 

m  h 


Fig.  32.  Ideal  longitudinal  section  of  an  insect,  showing  relative  position  of  organs 

a,  alimentary  canal ;  /;,  heart ;  ;«,  muscle  bands  ;  ;;,  ner\'e  cord  ;  ;',  reproductive  organs. 

(After  Comstock) 

Just  beneath  the  back  is  a  small,  transparent  tube,  the  dorsal  blood 
vessel,  or  heart.  Along  the  median  line,  close  to  the  ventral  wall, 
is  a  series  of  small  white  knots,  or  ganglia,  connected  by  a  double 

28 


ANATOMY  OF  INSECTS  —  INTERNAL 


29 


cord,  which  form  the  nervous  system.  On  either  side  of  each  seg- 
ment is  a  small  opening  through  the  body  wall,  called  a  spiracle, 
through  which  air  is  admitted  to  the  breathing  tubes,  which  branch 
to  all  parts  of  the  body  and  form  the  respiratory  system.  The  re- 
prdductive  organs  are  found  in  the  posterior  segments  of  the  abdo- 
men and  have  a  separate  opening  just  below  the  anus. 

The  digestive  system.  The  digestive  tract,  or  alimentar}-  canal, 
consists  of  a  more  or  less  straight  tube,  occupying  the  larger  part  of 
the  center  of  the  body  and  divided  into  parts  with  special  functions, 
whose  development  depends  upon  the  food  habits  of  the  insect. 

Pharynx.  The  food,  after  being  torn  to  pieces  and  ground  up 
by  the  mouth-parts,  is  received  into  the  pJiary}ix  (often  called  the 


Fig.  -^Tj.    Digestive  and  excretory  system  of  a  grasshopper 


r,  crop ;  g,  gizzard,  or  proventriculus  concealed  by  caeca ;  g.c^  gastric  caeca ;  /./,  large  intes- 
tine ;  ;«,  mouth  ;  m.t,  Malpighian  tubes  ;  o,  esophagus ;  r,  rectum ;  s^  stomach  ;  s.g^  salivary 
glands  ;  s.i,  small  intestine 

mouth),  lying  within  the  head,  and  in  which  it  is  acted  upon  by  the 
saliva.  In  sucking  insects  the  pharynx  acts  as  a  pumping  organ,  as 
already  described.  The  saliva  is  secreted  by  the  salivary  glands, 
which  lie  along  the  esophagus  in  the  thorax,  whose  ducts  open  at 
the  base  of  the  tongue  (hypophan-nx).  The  saliva  acts  on  starch, 
changing  it  into  glucose  as  in  the  vertebrates  ;  in  some  carnivorous 
insects  it  acts  on  the  proteids  and  is  sometimes  used  to  poison  the 
prey ;  in  mosquitoes  the  poisonous  saliva  prevents  the  coagu- 
lation_i]£_the_blood_ofanimals,  though  its  original  function  may 


?o 


ELEMENTARY  ENTOMOLOGY 


have  been  to  act  on  the  proteids  of  plant  juices.  In  most  cater- 
pillars, of  which  the  silkworm  is  the  best  example,  and  in  many 
other  insect  larvae,  certain  salivary  glands  have  become  specialized 
so  that  their  secretion  hardens  upon  coming  in  contact  with  the  air 
and  forms  the  silk  of  which  their  cocoons  are  spun. 

Esophagus.    The  esophagus  is  a  straight  tube  passing  from  the 
pharynx  to  the  crop  or  gizzard,  or  directly  into  the  stomach. 

Crop.    The  crop  is  practically  a  dilation  of  the  posterior  end  of 
the  esophagus  and  in  herbivorous  insects  forms  the  larger  part 

of  the  digestive  tract.  The  food  is 
stored  in  the  crop  until  the  action 
of  the  saliva  has  been  completed, 
changing  the  starches  into  glucose 
sugar  and  the  albuminoids  into  as- 
similable, peptonelike  substances. 
In  many  insects  which  feed  on 
liquids,  the  storage  capacity  of  the 
crop  is  increased  by  a  lateral 
pocket,  which  in  some  cases  forms 
a  separate  sac  communicating  with 
the  crop  by  a  short  neck.  The 
walls  of  the  crop  contain  a  layer  of 
muscles  which  force  the  food  back 
into  the  gizzard  when  it  is  suffi- 
ciently digested. 

Gizzard.  The  gizzard  [proven- 
tnculns)  is  found  best  developed 
in  biting  insects,  such  as  grass- 
hoppers and  beetles,  which  feed 
on  coarse  food,  and  is  but  slightly 
developed  or  absent  in  many  orders.  It  is  termed  "gizzard "  because 
it  somewhat  resembles  the  gizzard  of  a  bird  and  was  supposed  to 
function  similarly.  It  is  a  small,  very  muscular  organ,  lined  within 
with  strong  chitinous  teeth,  or  ridges,  which  strain  the  food,  pre- 
venting the  passage  of  large  particles  into  the  true  stomach.  Some 
have  thought  that  these  ridges  aid  in  grinding  the  food,  but  this 
seems  doubtful.  Usually  a  valve  allows  the  food  to  be  forced  from 
the  gizzard  back  into  the  stomach,  but  prevents  its  return. 


Fig.  34.  Cockroach  dissected  to  show 
ahmentary  canal  and  bands  of  muscles 

alx,  alimentary  canal.    (After  Hatshek  and 
Cori,  from  Jordan  and  Kellogg) 


ANATOMY  OF  INSECTS  —  INTERNAL 


Stomach.  The  stomach  {vcntriciilus)  is  usually  a  simple  tube 
somewhat  larger  in  diameter  than  the  esophagus  or  intestine,  but 
of  variable  size  and  strength.  As  the  food  passes  into  the  stomach 
it  is  acted  upon  by  the  secretions  of  the  ccccal  tubes  {gastric  caca) 
which  are  glandular  pouches,  or  tubes,  opening  into  the  anterior 
end  of  the  stomach.  Their  number,  size,  and  shape  are  quite  vari- 
able, and  they  secrete  a  weak  acid  which  emulsifies  fats  and  con- 
verts albuminoids  into  peptones.  The  stomach  is  not  lined  with 
chitin,  as  is  the  rest  of  the  alimentary  tract,  but  is  glandular  and 
secretes  a  neutral  or  alkaline  fluid  which  aids  in  the  further  diges- 
tion of  the  food.  The  chief  function  of  the  stomach,  however,  is 
to  absorb  the  digested  food  and  pass  it  into  circulation. 


Fig.  35.    Digestive  canal  of  a  carabid  beetle 

/i,  esophagus  ;  c,  crop  ;  d,  proventriculus  ;  /,  stomach  with  its  caeca  ;  g,  posterior  portion 
of  stomach  ;   //,  intestine  ;  /,  two  pairs  of  Malpighian  tubes  ;   k,  rectum  ;  /,  anal  glands.    ' 

(After  Dufour) 

Intestine.  The  food  passes  from  the  stomach  into  the  intestine 
through  a  pyloric  valve  which  prevents  its  passage  backward.  The 
intestine  is  divided  into  three  fairly  distinct  parts,  the  ileum,  colon, 
and  recttnn.  The  length  and  size  of  these  parts  varies  greatly  ac- 
cording to  the  food  of  the  insect,  the  ileum  often  being  considerably 
coiled.  In  the  ileum  the  digested  food  materials  are  absorbed  and 
passed  into  the  blood  circulation  ;  the  colon,  which  is  often  absent, 
contains  undigested  matter  and  waste  products  ;  while  the  rectum 
has  thick,  muscular  walls  and  expels  the  feces  through  the  anus, 
which  opens  through  the  last  segment  of  the  abdomen. 

Malpighian  tubes.  Opening  into  the  intestine,  just  back  of  the 
stomach,  are  several  small,  slender  tubes,  variable  in  number,  in 
which  uric  acid  is  found,  and  which  are  considered  to  be  excretory 
organs  similar  in  function  to  the  kidnevs  of  hig-her  animals. 


32 


ELEMENTARY  ENTOMOLOGY 


When  arsenical  insecticides  are  applied  to  the  food  of  biting 

insects,  the  arsenic  must  be  in  the  most  insoluble  form,  to  avoid 

burning  the  foliage,  and  it  is  therefore  not  dissolved  until  it 
reaches  the  stomach,  when,  having  been  mixed 
with  the  digestive  juices  mentioned,  it  becomes 
sufificiently  soluble  to  be  absorbed  by  the  walls 
of  the  stomach  and  ileum.  Some  insects  are 
able  to  consume  a  large  amount  of  poison  before 
an  amount  sufficient  to  kill  them  is  dissolved 
and  absorbed.  In  such  cases  poisons  are  some- 
times of  no  avail,  because  serious  injury  is 
done  before  the  pest  is  brought  under  control, 
and  other  means  must  be  employed. 

In  the  young 
stages  of  insects 
the  digestion, 
and  consequent 
growth,  is  ex- 
tremely rapid. 
A  caterpillar 
will  frequently 
eat  and  digest 

two  or  three  times  its  own  weight 

in   a  day.     Thus    the   silkworm, 

when   it  hatches  from   the  egg, 

weighs  but  one  twentieth    of   a 

grain,  but  in  56  days,  when  full 

grown,  it  has  consumed  120  oak 

leaves,  weighing  three  fourths  of 

a  pound,  and  half  an  ounce  of 

water,  or  86,000  times  its  original 

.  r      1  •   1     r       1  •  'Pig.  37.      Diagram    to    indicate    the 

weight,  of  which  food  207  grains     ^o^rse  of  the  blood  in  the  nymph  of 

have  been  assimilated,  one  fourth  a  dragon-fly 

of   a    pound    has    been    voided    as      a,  aorta;    /i,  heart.    The  arrows   show  the 

excrement,  and  five  ounces  have    ''""''" ''"'^^li'^Tro^'X  '"'" 
evaporated  as  water. 

Circulatory  system.   The  /j/ood  vessels  of  an  insect  are  exceed- 
ingly simple,  consisting  of  a  single  dorsal  tube,  or  heart,  which 


Fig.   36.      Diagram 

of  a  portion  of  the 

heart  of  a  dragon-fly 

nymph 

0,  ostium  ;  f,  valve. 
The  arrows  indicate 
the  course  of  the  blood. 
(After  Kolbe,  from 
Folsom) 


ANATOMY  OF  INSECTS  — INTERNAL 


33 


extends  the  length  of  the  body  along  the  median  line  just  beneath 
the  notum.  In  the  abdomen  of  adult  insects  this  tube  is  divided 
into  several  chambers,  each  of  which  has  a  valve  at  either  side, 
allowing  the  blood  to  flow  into  it  but  preventing  its  escape.  The 
chambers  are  also  separated  by  valves  which  allow  the  blood  to 
flow  forward  but  prevent  its  backward  passage.  The  abdominal 
part  of  the  tube,  the  heart  proper,  pulsates  and  drives  the  blood 
toward  the  head,  while  the  forward  part  is  a  simple  blood  vessel, 
called  the  aorta,  which  usually  divides  in  the  head,  where  it  ends 
abruptly,  allowing  the  blood  to  flow  into  the  body  cavity.  Thus  the 
blood  is  admitted  to  the  heart  by  the  lateral  valves,  is  forced  forward 
to  the  head,  and  thence  flows  in  more  or  less  defined  currents 


Y\G.  38.    Portion  of  a  trachea  of  a  caterpillar,  with  its  branches 
(After  Leydig,  from  Gegenbauer) 

throughout  the  body,  bathing  all  the  organs.  The  pulsation  of  the 
heart  and  the  flow  of  the  blood  may  be  observed  in  many  thin- 
skinned  larvae  and  nymphs. 

The  blood  consists  of  a  watery  fluid,  —  the  plasma,  or  serum,  — 
and  the  white  corpuscles,  or  leucocytes.  Usually  colorless,  it  is 
often  yellowish  or  greenish.  The  blood  has  almost  nothing  to  do 
with  the  aeration  of  the  tissues,  that  being  done  by  the  respiratory 
system,  as  described  below,  its  chief  function  being  to  nourish  the 
tissues  with  the  food  materials  that  it  carries. 

Respiratory  system.  Insects  have  no  lungs,  but  breathe  through 
a  system  of  tubes,  called  trachea,  which  extend  to  all  parts  of  the 
body,  bringing  fresh  air  to  the  tissues  and  carrying  off  the  carbon 
dioxide.    On  either  side  of  two  thoracic  segments,  and  on  all  the 


.34 


ELEMENTARY  ENTOMOLOGY 


abdominal  segments  but  the  last  two  or  three  are  small  openings 
called  spiracles,  or  stigmata,  which  are  the  external  openings 
through  which  air  is  admitted  to  the  trachea.  The  spiracles  are 
guarded  by  hairs  and  other  devices,  to  prevent  the  ingress  of  dust 
and  foreign  matter,  and  each  has  a  valve  operated  by  a  special  muscle 
which  opens  and  closes  it.  From  each  spiracle  a  short  tube  extends 
inward  and  opens  into  a  main  tracheal  tube  which  extends  along 
the  side  of  the  body.   There  are  commonly  two  of  these  main  tubes, 

or  tracheal  trunks,  on  either  side  of 
the  body,  which  give  off  three  main 
branches  in  each  segment.  The  upper 
branch  goes  to  the  dorsal  muscles,  the 
middle  one  branches  to  the  alimentary 
canal  and  reproductive  organs,  and  the 
lower  one  supplies  the  nerve  cord  and 
ventral  muscles.  These  branches  divide 
and  subdivide  into  the  finest  tubes, 
which  penetrate  all  the  tissues,  run- 
ning between  the  muscle  fibers ;  some 
authorities  state  that  they  may  even  en- 
ter individual  cells.  They  do  not  end 
blindly,  but  anastomose  so  as  to  form 
a  capillary  network,  so  that  a  contin- 
uous circulation  of  air  is  possible.  By 
opening  the  spiracles  the  air  enters 
the  tracheal  system,  and  it  is  expelled 
by  muscles  which  cause  a  vertical  con- 
traction of  the  body  walls  and  thus 
force  it  out.  The  rhythmic  expansion 
and  contraction  of  the  body  occurs  at 
a  regular  rate,  dependent  upon  the 
temperature  and  the  activity  of  the  insect,  and  resembles  the 
breathing  of  higher  animals.  Many  insects  are  provided  with 
large  air  sacs  which  serve  as  air  reservoirs.  The  trachea  are 
readily  recognized  by  their  striated  appearance,  which  is  due  to 
a  thickening  of  the  cuticle  into  a  thread,  which  lies  on  the  inner 
surface  in  a  compact  spiral,  like  a  compressed  spiral  spring,  and 
thus  prevents  the  collapse  of  the  tubes. 


Fig.  39.    Diagram  of  tracheal 
system  in  body  of  a  beetle 

sp,  spiracles ;    ii\  trachea.     (After 
Kolbe) 


ANATOMY  OF  INSECTS —  INTERNAL 


In  aquatic  insects  various  respiratory  devices  have  been  developed. 
Many  of  them  (May-fly,  dragon-fly,  stone-fly,  and  mosquito  nymphs) 
bear  tracheal  gills  which  consist  of  a  leaflike  expansion,  or  a  tuft  of 
thin  filaments,  into  which  the  trachea  extend  and  divide  into  a  fine 
network.  The  oxygen  of  the  water  passes  through  the  gill  mem- 
brane into  the  air  of  the  trachea,  and  thus  the  air  of  the  tracheal 
system  is  purified.  No  true  gills, — that  is,  gills  carrying  blood 
vessels,  like  those  of  fishes,  —  are  found  in  insects.  Other  aquatic 
insects  carry  a  thin  film  of  air  with  them,  either  by  means  of  a 
thick  coating  of  fine  hairs  to  which  air  bubbles 
adhere,  or  beneath  the  wing-covers.  The  trachea 
are  sometimes  prolonged  into  tubes  which  pro- 
ject beyond  the  tip  of  the  abdomen  and  extend 
to  the  surface  of  the  water  or  mud  in  which 
these  insects  live. 

From  the  above  description  it  is  evident  that 
insects  possess  the  best-developed  t)'pe  of  respir- 
atory system,  extending  as  it  does  to  all  the 
tissues  of  the  body,  giving  them  a  constant 
supply  of  fresh  air  and  carrying  off  the  waste 
gases.  With  an  ample  food  supply  this  makes 
possible  a  rapid  oxidation  of  the  tissues,  and 
undoubtedly  is  one  of  the  chief  reasons  for  the 
wonderful  muscular  activity,  working  power,  and 
endurance  of  insects. 

The  structure  of  the  respiratory  system  is  of  great  practical  im- 
portance in  combating  insect  pests.  Many  insects  which  cannot 
be  destroyed  with  arsenical  poisons  are  killed  by  contact  insecti- 
cides in  either  a  spray  or  a  dust  form.  These  contact  insecticides 
destroy  the  insect  by  entering  or  clogging  the  spiracles  or  trachea. 
Oils  are  particularly  valuable  because  they  spread  and  pass  readily 
through  the  hairs  which  guard  the  spiracles.  Soap  solutions  leave  a 
gummy  deposit,  when  the  water  evaporates,  which  clogs  the  trachea. 
Finely  divided  dusts,  such  as  fine  tobacco  dust,  pyrethrum,  and 
even  air-slaked  lime  or  road  dust,  will  clog  the  spiracles  of  many 
insects.  Insects  living  in  grain,  stored  products,  and  other  inac- 
cessible places  are  often  destroyed  by  the  use  of  poisonous  gases, 
such  as  carbon  bisulphide  and  hydrocyanic  acid  gas,  which  quickly 


Fig.    40.     Diagram 

of  trachea  in  head 

of  cockroach 

/,  trachea,  or  air  tubes. 
Note  branches  to  all 
the  mouth-parts  and 
the  antennas.  (After 
Miall  and  Denny) 


36 


ELEMENTARY  ENTOMOLOGY 


asphyxiate  them  through  the  well-developed  tracheal  system,  though 
occasionally  the  valves  of  the  spiracles  are  so  well  developed  that 
an  insect  may  keep  them  closed  for  a  long  time,  so  that  fumiga- 
tion, in  order  to  be  fatal,  must  be  prolonged. 

Muscular  system.  Insects  are  well  provided  with  powerful  mus- 
cles, a  caterpillar  having  some  two  thousand.  The  muscles  are 
yellowish  in  color,  and  the  fibers  are  striated  as  in  the  voluntary 
muscles  of  vertebrates.  The  simplest  type  of  muscles  is  found  in 
larvae  and  in  the  abdominal  segments  of  adult  insects,  where  the 


abc 


Fig.  41.    Muscles  of  cockroach,  of  ventral,  dorsal,  and  lateral  walls,  respectively 

a,  alary  muscle  :  (i/>c;  abductor  of  coxa ;  ai/c,  adductor  of  cojcji ;  /s,  longitudinal  sternal ;  //, 

longitudinal  tergal ;    //A,  longitudinal  thoracic  ;    os,  oblique  sternal ;    ts,  tergo-sternal ;    /jl, 

first  tergo-sternal.    (After  Miall  and  Denny) 

muscles  of  each  segment  are  very  similar,  forming  segmented 
bands  on  the  inside  of  the  body  wall.  The  longitudinal  muscles 
beneath  the  tergum  and  above  the  sternum  are  arranged  so  that, 
when  they  contract,  the  body  bends  in  that  direction,  and  by  their 
rhythmic  contraction  the  looping  walk  of  the  caterpillar  is  produced. 
Oblique-sternal  muscles  bend  the  abdomen  laterally,  and  vertical 
muscles  draw  the  tergum  and  sternum  together  in  expiration.  The 
thorax  of  adult  insects  is  filled  with  the  strong  muscles  which 
operate  the  wings  and  legs,  and  the  muscles  which  operate  the 
mouth-parts  occupy  the  back  of  the  head. 


ANATOMY  OF  INSECTS  —  INTERNAL 


Z7 


The  work  performed  by  the  muscles  of  insects  appears  prodigious 
compared  with  that  done  by  higher  animals.  Thus  the  weakest 
insect  can  pull  over  twenty  times  its  weight.  A  house-fly  can 
carry  a  match,  to  equal  which  a  man  would  need  to  carry  a  timber 
thirty-five  feet  long  and  as  large  around  as  his  body.  An  earwig  can 
lift  twelve  times  its  weight,  and  a  honey-bee,  in  flight,  carries  four 
fifths  of  its  weight.  A  small  insect  is  relatively  stronger  than  a  large 
one,  and  the  relative  strength  of  insects  is  largely  accounted  for  by 
their  small  size.  This  is  due  to  the  fact  that  the  weight  increases  as 
the  cube  of  a  single 
dimension,  while  the 
strength  of  a  muscle 
increases  as  the  square 
of  its  diameter.  The 
endurance  and  rapidity 
of  muscular  action  of 
insects  is  no  less  mar- 
velous. By  determin- 
ing the  pitch  of  the 
note  made  by  the  wing 
vibrations  of  a  gnat, 
physicists  have  shown 
that  its  wings  may  move 
as  much  as  fifteen  thou- 
sand times  per  minute. 
The  prolonged  vibra- 
tion of  the  honey-bee's 
wings  is  another  instance  of  remarkable  muscular  endurance. 

Nervous  system.  The  nervous  system  consists  of  a  series  of 
small  white  ganglia  which  are  connected  by  a  double  nerve  cord 
lying  along  the  bottom  of  the  body  cavity.  In  the  larvae  there  is 
usually  one  ganglion  to  each  segment,  but  in  the  adult  insects 
the  ganglia  are  often  fused  together,  those  of  the  thorax  and  an- 
terior abdominal  segments  having  grown  together,  as  well  as  those 
toward  the  tip  of  the  abdomen.  In  the  head  the  ganglia  have 
grown  together  to  form  the  brain,  which  lies  just  above  the  esoph- 
agus and  which  is  connected  with  the  subesophageal  ganglion  by 
a  double  nerve  cord,  one  commissure  of  which  passes  on  either  side 


Fig.  42.    Nervous  system  of  honey-bee,  at  a,  and 

of  its  larva,  at  b,  showing  the  simple  type  of  the 

larva   and  the  specialization   in   the   adult  due  to 

fusion  of  the  ganglia 


38 


ELEMENTARY  ENTOMOLOGY 


of  the  esophagus,  thus  forming  a  nerve  collar.  The  brain  gives 
off  nerves  to  the  eyes,  antennae,  palpi,  and  other  sensory  organs 
of  the  head,  receiving  the  sensory  stimuli  and  controlling  the  coor- 
dinated muscular  movements.  In  a  general  way  the  brain  is  the 
seat  of  whatever  "will"  an  insect  may  have.  The  subesophageal 
ganglion  coordinates  the  movements  of  the  mouth-parts,  as  well 
as  some  bodily  movements.  The  thoracic  and  abdominal  ganglia 
give  off  nerves  to  all  parts  of  their  segments,  the  movements  of 
which  they  control.     They  are   more  or  less   independent,   each 


Fig.  43.  Nervous  system  of  head  of  cockroach 

a,  antennal  nerv'e  ;  a^,  anterior  lateral  ganglion  of  sympathetic  system  ;  i,  brain  ;  d,  salivary 
duct ;  /,  frontal  ganglion  ;  /i,  hypopharynx  ;  /,  labrum  ;  //,  labium  ;  m,  mandibular  nerve  ;  i/ix, 
maxillary  nerve ;  «/,  nerve  to  labrum  ;  n/i,  nerve  to  labium  ;  0,  optic  nerve ;  oc,  esophageal 
commissure ;  oe,  esophagus ;  /^,  posterior  lateral  ganglion  of  sympathetic  system  ;  r, 
recurrent  nerve  of  sympathetic  system  ;   s,  subesophageal  ganglion.    (After  Hofer,  from 

Folsom) 

forming  a  nerve  center  for  its  segment.  Thus  a  decapitated 
insect  will  walk  or  fly,  and  the  abdomen  of  a  grasshopper  will 
continue  to  breathe,  these  functions  being  controlled  by  the  seg- 
mental ganglia,  though  lacking  coordination.  In  addition  to  the 
main  nervous  system  there  is  a  sympathetic  system,  one  part  of 
which  runs  along  the  upper  part  of  the  alimentary  canal  and  con- 
trols the  digestive  process,  while  a  small  ventral  sympathetic  nerve 
gives  off  branches  which  control  the  spiracle  muscles. 

Dr.  J.  B.  Smith,  in  his  "  Economic  Entomology,"  gives  an 
interesting  account  of  some  experiments  which  show  the  relation 
of  the  brain  and  ganglia  to  the  body  : 


ANATOMY  OF  INSECTS  —  INTERNAL 


I  found  that  if  I  cut  off  the  abdomen  completely,  the  fly  would  live  for 
twenty-four  hours  thereafter ;  with  practically  no  digestive  system,  and  with 
most  of  its  heart  gone.  Turning  the  matter,  I  cut  off  the  head,  and  found  that 
it  would  live  without  a  head  for  just  about  as  long  a  time  as  it  would  without 
an  abdomen.  Of  course  death  was  bound  to  result  from  this  mutilation  in 
time,  but  the  interesting  feature  is  that  no  apparent  symptom  of  pain  developed. 
I  found,  however,  that  just  as  soon  as  I  cut  the  large  ganglion  in  the  middle 
of  the  thorax  I  terminated  life.  Whatever  sentimental  feeling  there  may  be 
in  the  matter  of  causing  unnecessary  pain,  there  is  no  reason  to  believe  that 
insects  have  any  well-developed  sensitiveness,  as  we  understand  that  term. 
The  character  of  the  insect  nervous  system  is  so  entirely  different  from  that 
of  our  own  that  we  are  left  without  real  guides  in  our  interpretation  of  the 
various  sensitive  structures.  Man  judges  most  things  by  himself,  and  where 
this  guide  fails,  he  is  at  a  loss  and  cannot  be  certain  that  he  interprets  what  he 
sees  correctly. 

The  senses  of  insects.  Sight.  Attention  has  already  been  called 
to  the  simple  eyes,  or  ocelli,  and  the  compound  eyes.  An  ocellus 
consists  of  a  lens,  vitreous 
bod}',  retina,  and  nerve,  much 
like  the  eye  of  vertebrates, 
but  its  form  is  fixed,  and  as 
there  is  therefore  no  power  of 
accommodation  to  the  distance 
between  it  and  the  object  seen, 
its  power  of  vision  must  be 
extremely  limited.  As  far  as 
the  ocelli  are  concerned,  in- 
sects must  be  very  nearsighted, 
for  they  are  quite  convex  and 
will  only  focus  at  one  distance, 
which  must  be  short.  Ex- 
periments have  shown  that 
light  and  darkness  are  distin- 
guished by  the  ocelli,  for  if  the  Fig.  44.  structure  of  median  ocellus  of 
compound  eyes  of  a  grasshop-  honey-bee,  in  sagittal  section 

per  are   covered   with  varnish,      /',  hypodermis ;   /,  lens ;   «,  nerve  ;  /,  iris  pig- 

,V  ^^^   C^A   ;*-,.  „ ^,,4-  ^C  „  U^         ment;  ;-,  retinal  cells;  v,  vitreous  body.    (After 

It  can  find  its  way  out  of  a  box  Redikorzew,  f^m  Folsom) 

with  a  single  opening.    Prob- 
ably the  ocelli  are  of  more  service  in  this  way  than  in  forming 
definite  images,  though  insect  larvas  possess  only  ocelli. 


40 


ELEMENTARY  ENTOMOLOGY 


I  < 


The  surface  of  the  compound  eye  is  composed  of  numerous 
hexagonal  facets,  each  of  which  is  the  end  of  a  single  eye  element 

called  an  ommatidium,  which  is  prac- 
tically a  separate  and  distinct  eye. 
Each  ommatidium  is  composed  of  the 
various  optical  elements  necessary  for 
vision,  but  it  receives  impressions  only 
in  a  straight  line,  which  form  only  a 
very  small  part  of  the  total  field  of  the 
insect's  vision.  This  is  due  to  the  fact 
that  each  ommatidium  is  surrounded 
by  black  pigmented  cells,  which  ab- 
sorb or  reflect  the  light,  as  shown  in 
Fig.  46,  so  that  only  those  rays  which 
come  in  a  straight  line  impress  the 
retina.  Thus  the  whole  view  formed 
by  the  images  from  all  the  ommatidia 
as  they  reach  the  optic  nerve  must  be 
like  that  of  a  mosaic. 

Insects  are  able  to  distinguish  forms 
at  but  relatively  short  distances,  vary- 
ing  from   two   to   five   feet,   and  to 


Fig.   45.     Portion   of  compound 

eye  of  fly  {Calliphora  vomitoria), 

radial  section 

f,  cornea ;  /,  iris  pigment ;  «,  nerve 
fibers  ;  iic^  nerve  cells  ;  r,  retinal  pig- 
ment;    t,  trachea.     (After   Hickson, 
from  Folsom) 


see  distinctly  only  near-by  objects. 
Large  eyes,  as  those  of  the  dragon- 
fly, give  a  wide  field  of  vision, 
and  numerous  facets  would  give  a 
greater  distinctness  of  vision.  In- 
sects' eyes  are  well  adapted  to 
detect  motion,  as  a  moving  object 
affects  the  facets  in  succession,  and 
motion  is  thus  observed  without 
moving  the  eyes.  They  are  able 
to  distinguish  colors  and  often 
respond  quite  definitely  to  them, 
but  their  color  sense  seems  to 
have  a  different  range  from  that 
of  man,  as  ants  are  sensible  to  the 
ultra-violet  rays. 


Fig.  46.  Illustrating  mode  of  vision 
in  compound  eye 

"  The  light  enters  through  the  cornea. 
The  rays  which  strike  the  sides  of  each 
tube  or  cone  are  absorbed  by  the  black 
pigment  which  surrounds  the  tube.  Ac- 
cordingly those  rays  of  light  only  which 
pass  through  the  crystalline  cones  directly 
(or  are  reflected  from  their  sides),  such 
as  a-a' ,  b-b',  c-c',  d-d',  e-e',  will  ever  affect 
the  nerves  at  a',  b',  </,  d',  e'."  (After 
Lubbock,  from  S.  J.  Hunter) 


ANATOMY  OF  INSECTS  —  INTERNAL 


41 


Touch.  The  sense  of  touch  is  very  highly  developed  in  many 
insects,  sensory  tactile  hairs  commonly  occurring  over  the  whole 
body,  and  the  antennae,  palpi,  and 
cerci  being  specially  developed  as 
tactile  organs. 

Taste.  Both  observation  and 
experiment  have  shown  that  in- 
sects have  a  well-developed  sense 
of  taste,  though  it  is  often  quite 
different  from  that  of  man,  as 
they  detect  some  substances  but 
fail  to  perceive  others,  and  often 
seem  to  relish  substances  wholly 
repugnant  to  us.  The  sense  of 
taste  is  located  in  sensory  hairs  or  microscopic  pegs  borne  upon 
the  tongue  (see  Fig.  47),  or  hypopharynx,  on  the  epiphar}''nx  (a 


Fig.  47.    Tip  of  tongue  of  honey-bee 

Showing  labellum  {Ll'l),  guard  hairs  {Hi), 

and  ventral  groove   (-(■),  from  above  and 

below.     (After  Snodgrass,  United   States 

Department  of  Agriculture) 


Fig.  48.    Nerve  endings  in  tip  of  maxillary  palpus  of  (a)  Lociista  viriJissima, 
and  in  labial  palpus  of  {h)  Machilis polypoda.    (Greatly  magnified) 

sh,  sense  hairs  ;  sc,  sense  cells ;  be,  blood  cells.    (After  \'om  Rath,  from  Kellogg) 

sensor)^  portion  of  the  roof  of  the  pharynx  similar  to  the  palate  of 
higher  animals),  and  on  the  maxillary  and  labial  palpi.  Probably  the 
sense  of  smell  is  used  more  than  the  taste  organs  in  choosing  food. 


42 


ELEMENTARY  ENTOMOLOGY 


Fig.  49.    Sensory  cells 

in  antennas  of  aphides. 

(Greatly  magnified) 


Smell.    Most  insects  depend  upon  their  sense  of  smell  to  find 

their  food  and  to  discover  the  opposite  sex.  Thus  beetles  and  flies 
are  drawn  to  carrion  and^to  decaying  vegetation, 
and  in  almost  all  cases  it  seems  probable  that 
the  food  plant  of  an  insect  is  distinguished  by 
smell  rather  than  by  sight.  A  confined  female 
Cecropia  moth  will  often  draw  numerous  males 
from  a  considerable  distance.  Experiments 
have  shown  that  the  antennae  are  the  chief 
organs  of  smell,  though  the  maxillary  palpi 
and  cerci  detect  certain 
odors  and  enable  certain 
insects  to  smell  when  the 
antennae  are  removed. 
The  olfactory  function 
of  the  antennae  can  be 

very  easily  shown  by  taking  an  insect  which 

is  definitely  attracted  to  some  substance  by 

smell  and  removing  the  antennae  or  covering 
them  with  shellac,  when 
it  will  be  found  wholly 
indifferent  to  what  was 
previously  so  attractive. 
Vile-smelling  substances 
which   are   supposed    to 

repel    insects  are   usually      showing  smelling  pits  on  the 

of  no  value,   not  affect- 
ing the  insect  as  they  do 

man.  Some  attempts  have  been  made  to  utilize 
the  sense  of  smell  in  luring  insects  to  destruc- 
tion, but  as  yet  with  no  very  marked  success, 
though  there  is  promise  of  possible  control  of 
some  pests  in  this  way. 

Hearing.   There  is  no  evidence  that  hearing 

is  generally  developed  in  insects,  but  in  many 

groups  we  naturally  infer  its  presence  from  the 

fact  that  characteristic  noises  are  produced,  as  the  "singing"  of 

the  cicada  and   katydid.    These  noises  are  produced   in  various 


Fic.  50.    Antenna  of  la- 
mellicorn  beetle 


expanded  terminal  segments. 
(After  Jordan  and  Kellogg) 


Fig.  51.    Under  sur- 
face   of    right    wing 
of  the  male   cricket. 
(Enlarged) 

/,  rasp  ;  z,  position  of 
scraper,  only  scraper  of 
the  left  wing  used;  j, 
attachment  of  wing.  (Af- 
ter Linville  and  Kelly) 


ANATOMY  OF  INSECTS  —  INTERiNAL 


4, 


ways.  Thus  flies  and  bees  buzz  with  their  wings  in  rapid  vibra- 
tion, and  the  singing  of  the  male  cicada  is  produced  by  the  rapid 
vibration  of  a  pair  of  membranes  on  the  first  abdominal  segment. 
Many  beetles  squeak  by  rubbing  the  wing-covers  against  some  rasp- 
like part  of  the  body.  But  the  grasshoppers  and  crickets  are  the 
leaders inJJie_iiisectorcij£stra.  Grasshoppers  often  produce  noises 
in  flying  by  rubbing 

7 


the  hind  legs  against 
the  wing-covers  or 
by  rubbing  together 
the  front  and  hind 
wings.  Katydids 
and  crickets  have 
the  best-developed 
musical  apparatus, 
having  a  scraper 
on  the  base  of  one 
wing-cover  and  a 
vein  ridged  like  a 
file  on  the  base  of 
the  other,  which, 
when  rubbed  to- 
gether, vibrate  the 
neighboring  mem- 
brane and  produce 
the  strident  song, 
or  the  shrill  chirp, 
so  characteristic  of 
these  insects. 


Fig.  52. 


Ear  of  locust  (Caloptonts  italicin) 
the  inner  side 


seen  from 


T,  tympanum  :  77?,  its  border ;  0,  21,  two  bonelike  processes  ; 
bi,  pear-shaped  vesicle  ;  ii,  auditory  nerve  ;  ga,  terminal  gan- 
glion ;  sf,  stigma,  or  spiracle ;  m,  opening  muscle,  and  wi, 
closing  muscle  of  same  ;  .1/,  tensor  muscle  of  the  tympanic 
membrane.    (After  Graber) 


That  these  sounds  are  heard  by  their  mates  is  shown  by  the 
answering  call  of  one  to  another,  and  to  similar  tones  produced 
artificially.  In  grasshoppers  a  large  auditory  organ,  or  "  ear,"  is 
found  on  either  side  of  the  first  abdominal  segment.  It  consists  of 
a  surface  membrane,  or  tympanum,  stretched  over  a  cavity,  on  the 
inner  surface  of  which  rest  two  processes,  analogous  to  the  small 
bones  of  the  human  ear,  which  carry  the  vibration  to  a  delicate 
vesicle  which  connects  with  an  auditory  nerve.  Similar  small 
membranes  are  found  on  the  fore-tibia  of  certain  insects  and  are 


44 


ELEMENTARY  ENTOMOLOGY 


considered  probably  auditory.  In  male  mosquitoes,  and  probably  in 
some  other  forms,  the  antennae  have  an  auditory  function  which 
enables  them  to  find  the  females,  as  is  shown  by  their  vibrating  in 
unison  with  a  tone  produced  by  a  tuning  fork  of  the  same  pitch 
as  that  made  by  the  female  with  her  wings. 


Fig.  53.    Female  mosquito 

Showing  auditory  hairs   {ak)  on  the 
antennas.  (After  Jordan  and  Kellogg) 


Fig.  54.  Diagram  of  longitudinal  section 
through  first  and  second  antennal  segments 
of  a  mosquito  {Mochlonyx  culict'/ormis),  male, 
showing  complex  auditory  organ  composed 
of  fine,  chitinous  rods,  nerve  fibers,  and  nerve 
cells.    (Greatly  magnified) 

(After  Child,  from  Kellogg) 


CHAPTER  V 

THE  GROWTH  AND  TRANSFORMATIONS  OF  INSECTS 

Stories  of  the  lives  of  insects,  or  their  "  hfe  histories,"  are 
among  the  most  interesting  and  marvelous  to  be  found  in  the 
realm  of  science,  furnishing  themes  for  poet,  philosopher,  and 
scientist. 

Egg.  All  begin  life  in  the  egg  stage.  The  shape,  size,  number, 
and  position  of  the  eggs  are  as  different  as  are  the  many  families 
of  insects,  and  cannot  be  described  in  general  terms.   Usually  they 


m,  n  o  p  q  r  s 

Fig.  55.    Eggs  of  different  insects.    (Enlarged) 

a,  Toririx  ;  b,  Liparis  ;  r,  a  Noctuid ;  (/,  usual  shape  of  those  of  a  bark  borer  ;  e,  May-beetle 
{Lachnostertid)  ;  /,  midge  (Chiro)iomus) ;  g,  Lyda  ;  h,  fly  {Miisca) ;  /,  honey-bee  ;  k^  gall-fly 
{Rhodites  rosae)  ;  /,  lace-winged  fly  {Cluysopa) ;  wz,  pomace-fly  {Drosophila)  ;  ;;,  Peniatoma: 
0,  back-swimmer  {IVefa) ;  /,  butterfly  {Pieris  crataegi) ;  q,  bedbug ;  r,  louse,  fastened  to  a 
hair;  s,  bot-fly  {Hyfoderma).    (After  Judeich  and  Nitsche,  from  Packard) 

are  laid  upon  the  food  plant,  or  host,  but  occasionally  their  position 
could  not  be  accounted  for  were  the  habits  of  the  young  not  known. 
The  number  laid  by  a  female  may  vary  from  one  or  two,  as  in  the 
case  of  some  aphides,  to  many  thousands,  as  in  bees  and  termites, 
but  a  fair  average  would  probably  be  about  one  hundred.  The  size 
varies  inversely  with  the  number  produced,  and  the  shape  and  struc- 
ture are  largely  influenced  by  the  environment  in  which  the  eggs  are 
laid.  In  a  few  cases  the  eggs  hatch  within  the  body  of  the  female, 
which  thus  gives  birth  to  live  young,  as  do  the  aphides.  Those 
eggs  which  hatch  during  the  summer  have  an  incubation  period  of 
from  a  day  or  two,  as  do  those  of  certain  flies  and  mosquitoes,  to 

45 


46 


ELEMENTARY  ENTOMOLOGY 


three  or  four  weeks,  while  very  many  remain  dormant  over  winter 
and  hatch  when  sufficient  temperature  occurs  the  next  spring  or 
summer. 

Transformations.  Upon  hatching  from  the  egg  the  young  grass- 
hopper is  of  much  the  same  general  appearance  as  when  full  grown, 
and  is  readily  recognized  as  a  grasshopper ;    but  if  we  did  not 


Fig.  56.   Molting  of  the  full-grown  nymph  of  the  periodical  cicada,  showing  process 
of  emerging  from  the  skin  of  the  nymph,  with  the  soft  white  adults  below 

The  adults  become  black  after  hardening  for  a  few  hours 


know  that  the  little  caterpillar,  after  completing  its  growth,  finally 
transforms  into  a  butterfly,  we  should  never  suspect  them  to  be 
different  stages  of  the  same  insect,  and  a  lack  of  knowledge  of 
these  transformations  has  caused  many  strange  superstitions  con- 
cerning insects. 

The  transformation  of  the  butterfly  from  the  caterpillar  is  a 
complete  one,  and  is  known  as  a  complete  metaviorpJiosis.    The 


GROWTH  AND  TRANSFORMATIONS  OF  INSECTS 


47 


Fig.  57.   Nymph  of  lubber  grasshopper  {Dictyophora 

reticulata) ;  similar  to  the  adult  (Fig.  105)  in  general 

form,  except  in  lacking  wings 


growth  of  the  grasshopper,  on  the  other  hand,  is  gradual  and 
presents  no  striking  changes,  and  is  known  as  an  incomplete 
vietmnorphosis. 

Growth.  The  hard,  chitinous  skin  which  ser\-es  the  insect  as 
an  outer  skeleton  has  already  been  described,  and  furnishes  an  obvi- 
ous obstacle  to  its  rapid  growth.    When  the  insect  has  grown  to 

the  limit  of  this  outer 
shell,  its  predicament 
is  solved  in  the  only 
possible  way,  by  the 
skin  splitting  down  the 
middle  of  the  back 
and  being  sloughed 
off,  while  the  new  skin 
formed  beneath  the 
old  one  allows  further 
growth.  This  process, 
called  molting,  occurs 
in  all  insects,  as  well 
as  among  other  Arthropods,  the  skin  being  usually  shed  some 
four  or  five  times  during  growth,  though  some  species  molt  from 
ten  to  twenty  times. 

Incomplete  metamorphosis.  Young  insects  which  resemble  the 
adults,  as  those  of  the  grasshopper,  are  termed  nymphs.  After  the  sec- 
ond or  third  molt,  small  wing 
pads  appear  on  the  back, 
becoming  much  larger  with 
the  fourth  molt,  and  upon 

the     fifth     molt     the     adult       F^^-  58-    A  typical  larva,  the  cotton  bollworm 
...  or   corn-ear  worm;    totally  unlike    the   adult 

wmged  msect  emerges,  to  ^„,h  in  form 

feed  and  reproduce. 

Complete  metamorphosis.  The  caterpillar,  maggot,  or  grub  bear- 
ing no  resemblance  to  its  parents  is  called  a  larva.  The  larva 
grows  and  molts  several  times,  and  although  its  new  clothes  are 
sometimes  of  a  different  color,  they  are  all  cut  on  the  same  pattern, 
and  there  is  usually  no  marked  change  in  shape  or  structure  until 
the  larva  is  full  grown.  Upon  reaching  its  growth  the  larva  molts  for 
the  last  time  and  transforms  into  a  pupa.    The  pupa  is  a  dormant 


^^^1^^^^^ 


48 


ELEMENTARY  ENTOMOLOGY 


Fig.  59.    Cocoon  of  the  rusty  tussock  moth,  made  of  silk 
with  the  hairs  of  the  caterpillar  intermingled.    (Enlarged) 


Stage,  usually  inactive  and  taking  no  food,  resembling  neither  larva 
nor  adult,  in  which  the  tissues  and  organs  of  the  larva  are  re- 
constructed into 
those  necessary 
for  the  winged 
adult.  In  many 
pupae  the  wings 
and  legs  of  the 
adult  are  clearly 
distinguishable, 
closely  folded 
to  the  sides  of 
body,  but  in  the 
others  the  outer 
skin  of  the  pupa 

is  only  a  firm  shell  with  bare  outlines  of  the  adult  forming  within. 

Before  the  last  molt  many  larvae  burrow  into  the  ground,  where 

they  hollow  out  cells,  sometimes 

lined  with  silk  or  cement,  or  find 

other  suitable  secluded  places 

in  which  to  pupate.  The  cater- 
pillars of  moths  and  many  other 

larvae  spin  a  firm  casing  of  silk, 

called  a  cocooji,   in  which  they 

pupate .  B  utterfly  caterpillars  lash 

themselves  to  the  food  plant  by 

one  or  two  thick  strands  of  silk, 

and  the  pupa,  which  is  known 

as  a  chrysalis,  hangs  suspended 

by  the  tip  of  the  abdomen  with 

no  cocoon.  In  many  cases  in- 
sects hibernate  over  winter  in 

the  pupal  stage,  so  that  the  time 

of  the  pupal  life  varies  from  a 

few  days  in  summer  to  nine  or 

ten    months,    according  to  the 

habit    of    the    species.      Finally,       j,,^  ^o.   Cocoons  of  tiger  moth  cater- 

the  pupal  shell  splits  open  and  pillars  on  underside  of  loose  bark 


GROWTH  AND  TRANSFORMATIONS  OF  INSECTS     49 


the  adult  insect  emerges,  with  wings  soft  and  Hmp  but  expand- 
ing and  hardening  in  a  few  hours,  when  it  is  ready  to  seek  food 
and  a  mate. 

Thus  the  stages  of  growth  of  those  insects  having  a  complete 
metamorphosis  are  essentially  different  from  those  having  the  in- 
complete t}'pe,  as  indicated  in  the  following  summary' : 


Incomplete  metamorphosis 
Complete  metamorphosis  : 


P'crcr 
F"crcr 


Nymph,        Adult. 
Larva,  Pupa,    Adult. 


An  insect  never  grows  after  it  reaches  the  adult  stage.  The 
little  flies  which  appear  on  the  window  in  early  spring  are  not 
"baby"  flies  and  do  not  grow  larger,  but  are  entirely  different 
from  other  larger  species 
which  supersede  them 
later  in  the  season. 

The  life  histories  of 
insects  are  as  diverse  as 
are  the  species,  no  two 
being  quite  alike.  To 
study  and  carefully  deter- 
mine the  time,  place, 
and  manner  of  the  trans- 
formations is  one  of  the 
most  important  duties 
of  the  economic  ento- 
mologist, for  by  ascer- 
taining them  the  means 
of  control  of  injurious 
species  are  often  dis- 
covered. Many  insects 
may  thus  be  controlled 
by  simply  changing  gen- 
eral farm  methods,  such 
as  the  rotation  of  crops. 


Fig.  61.  Chrysalis  of  black  swallow-tailed  butterfly 
{Papilio  polyxencs) 

Showing  attachment  of  tip  of  abdomen  to  mass  of  silk 

threads    which    have    become    torn    from    around    the 

stem,  and  the  silken  loop  which  supports  the  thorax. 

(Photograph  by  Weed) 


the  time  of  plowing,  etc.,  which  result  in  the  prevention  or  mitiT  «-* 
gation  of  the  pest ;  or  a  knowledge  of  the  feeding  habits  may  in(%.  ^. 
cate  the  most  promising  means  of  attack,  and  successful  methodO      • 
may  be  determined  by  subsequent  experiments.  ^  W* 


50 


ELEMENTARY  ENTOMOLOGY 


A  better  appreciation  of  these  general  facts  concerning  insects' 
growth  will  be  secured  by  a  more  intimate  study  of  the  life  of  one 
or  two  of  each  of  the  types  of  metamorphosis. 

The  life  of  a  squash-bug  (Anasa  tristis).  Incomplete  metamor- 
phosis. About  the  time  that  squash,  cucumbers,  and  melon  vines 
begin  to  "  run,"  there  is  found  here  and  there  a  wilted  leaf,  which 
examination  shows  to  be  due  to  the  common  grayish-  or  brownish- 
black  squash-bug  which  has  just  emerged  from  hibernation.  If 
search  be  made  in  the  early  morning,  the  bugs  will  usually  be 

found  secreted  under 
clods  of  earth,  or  what- 
ever rubbish  may  be 
near  the  vines,  from 
which  they  emerge  to 
feed  during  the  day, 
flying  about  with  a 
characteristic  buzz. 

£j^^.  For  the  next 
month  or-six  weeks  the 
females  deposit  their 
eggs,  mostly  on  the  un- 
dersides of  the  leaves. 
The  eggs  are  oval, 
about  one  sixteenth 
inch  long,  attached  on 
one  side,  and  laid  in 
irregular-shaped  clus- 
ters arranged  in  rows  as  shown  in  Fig.  63,  from  three  or  four  to 
forty  eggs  being  found  in  a  cluster.  Newly  laid  eggs  are  a  pale 
yellow-brown,  which  grows  darker  a  day  or  two  before  hatching, 
so  that  the  approximate  development  may  be  determined  by  the 
color,  which  is  the  case  with  many  insects'  eggs. 

Nymph.  In  about  eleven  days,  the  exact  time  varying  from  six 
to  fifteen  days  according  to  the  temperature,  a  small,  disk-shaped 
piece  of  the  shell  is  forced  open  toward  one  end  of  the  Q.^g  and 
the  little  nymph  emerges.  The  newborn  buglet  is  brilliantly  col- 
ored and  is  quite  conspicuous  against  the  green  leaves,  the  antennas 
and  legs  being  a  bright  crimson,  the  head  and  anterior  thorax  a 


Fig.  62.  The  squash-bug,  adult  and  nymphs  of  first, 
third,  and  fifth  stages.  (About  twice  natural  size) 

(Photograph  by  Quaintance) 


GROWTH  AND  TRANSFORMATIONS  OF  INSECTS 


51 


lighter  crimson,  and  the  posterior  thorax  and  abdomen  a  bright 
green  ;  but  in  an  hour  the  crimson  darkens,  and  in  a  few  hours 

changes  to  a  jet- 
black.  The  young 
bugs  hatching  from 
a  cluster  of  eggs 
remain  together  in 
a  sort  of  family  dur- 
ing their  infancy, 
each  inserting  its 
tiny  beak  in  the 
succulent  leaf  from 
which  it  vigorously 
«v-  iHH^VSflllK         sucks  the  juice.    In 

J^*^        about     three     days 
Fig.  63.  Egg  masses  of  squash-bug.  (Twice  natural  size)     ^^^      abdomen      bc- 
(Photograph  by  R.  I.  Smith)  ■,.    ,         1     i    • 

comes  distended,  m- 
dicating  the  need  of  a  larger  suit  of  clothes  to  allow  further 
growth.  The  nymph  now  assumes  a  quiet  position,  the  skin  splits 
down  the  middle  of  the  back 
along  the  thorax  and  anterior 
abdomen,  and  gradually  the  little 
bug  pulls  itself  out  of  its  baby 


clothes,  the  time  required  for 
this  change  of  costume  vary- 
ing from  a  half-hour  to  several 
hours.  A  few  hours  later  the 
skin,  now  much  lighter  in  color, 
has  hardened,  and  the  insect  is 
about  one  fifth  inch  long.  The 
nymph  now  becomes  more  active 
and  alert  and  continues  to  feed 
some  nine  days  before  molting 
again.  In  the  third  stage  it  is 
considerably  larger  and  flatter, 
and  darker  in  color.  Eight  days 
later  the  third  molt  takes  place,  and  the  new  clothes  of  the  fourth 
stage  differ  in  having  small  but  distinct  wing  pads  extending  back 


Fig.  64.    Squasii-bug 

t7,  mature  female  ;  6,  side  view  of  head,  show- 
ing beak  ;  c,  abdominal  segments  of  male  ; 
if,  same  of  female,  (a,  twice  natural  size  ; 
/>,  c,  d,  more  enlarged.)  (After  Chittenden, 
United  States  Department  of  Agriculture) 


Fig.  65.    Squash-bugs  and  nymphs  at  work  on  a  young  plant.    (Natural  size) 

52 


GROWTH  AND  TRANSFORMATIONS  OF  INSECTS 


from  the  thorax.    In  another  week  the  skin  is  shed  for  a  fourth 
time,  and  the  fifth  stage  is  easily  recognized  as  a  full-grown  nymph, 

being  one  third  inch  long,  and 
the  wing  pads  and  thorax 
being  much  enlarged.  After 
feeding  for  another  nine  days 
it  molts  for  the  last  time  and 
transforms  to  the  winged  adult, 
the  whole  growth  having  re- 
quired from  four  to  five  weeks. 
Adult.  The  new  adults  be- 
come numerous  in  August,  but 
neither  mate  nor  lay  any  eggs 
during  that  season,  continuing 
to  feed  until  the  first  frosts  of 
autumn  blacken  the  leaves, 
when  they  rapidly  disappear 
into  winter  quarters.^  During 
the  middle  of  the  day  they  fly 
here  and  there  in  search  of 
suitable  hibernating  places,  and 
finally  hide  along  the  edges  of 
woodlands,  or  beneath  leaves, 
under  logs,  boards,  or  whatever 


Fig.  66.  First  three  stages  of  the  nymphs 
of  the  differential  locust.  (Much  enlarged) 


shelter  may  be  adjacent  to  the  garden,  where  they  remain  dormant 
until  called  back  to  activity  by  the  warm  sunshine  of  late  spring. 
Life  history  of  the  differential  locust  (Melanoplus  differentialis). 
Incomplete  metamorphosis.  Through- 
out the  Mississippi  Valley,  from  Illi- 
nois southward,  the  differential  locust 
is  one  of  the  most  common  and  de- 
structive grasshoppers,  and  is  an  excel- 
lent example  of  several  of  our  more 
abundant  and  injurious  species  whose 
life  histories  and  feeding  habits  are,  in  general,  very  similar. 


Fig.  67.    Egg  mass  of  the 
differential  locust 


1  The  life  history  as  given  is  for  New  England ;  farther  south  the  transforma- 
tions take  place  earlier  and  more  rapidly,  and  in  the  extreme  south  there  may  be 
more  than  one  generation. 


54 


ELEMENTARY  ENTOMOLOGY 


Nymphs.  The  little  grasshoppers  hatch  about  the  middle  of  May 
(though  we  have  observed  hatching  by  the  middle  of  March  in 
central  Texas)  and  are  of  a  dusky  brown  color  marked  with  yellow. 
The  head  and  legs  are  the  most  prominent  features  of  the  young 
nymph.  During  their  subsequent  growth  they  molt  five  times,  at 
intervals  of  from  ten  days  to  two  weeks,  the  relative  size  and  appear- 
ance of  the  different  stages  being  shown  in  Fig.  6"/ .  Professor 
H.  A.  Morgan,  who  made  a  careful  study  of  an  outbreak  of  this 

species   in    Mississippi    in 
1900,  has  given  an  inter- 


esting 

growth 

which 

quoted 


account  of  their 
and  habits,  from 
the     followinof     is 


Growtli.  The  young  on  first 
emerging  from  the  eggs  are 
sordid  white  and  after  an  airing 
of  an  hour  or  two  are  darker, 
assuming  a  color  not  unlike  the 
dark  gray  alluvial  soil  over 
which  they  feed.  There  are 
changes  of  color  as  the  earlier 
stages  are  assumed,  but  until 
the  close  of  the  third  stage  these 
changes  are  not  readily  percep- 
tible in  the  field  to  the  naked  eye. 
At  the  close  of  stage  four  the 
greenish-yellow  color  becomes 
prominent  on  many  forms,  and 
in  stage  five  the  greenish-yellow  and  yellow  ground  colors  predominate.  The 
vigorous  feeding  and  rapid  growth  of  the  young  in  stages  four  and  five,  and 
the  prominence  of  the  wing  pads  in  stage  five,  cause  the  grasshoppers  in 
these  conditions  to  appear  almost  as  conspicuous  as  adults. 

Habits.  The  habits  of  the  young  are  interesting,  and  a  knowledge  of  some 
of  them  may  be  helpful  in  developing  remedies.  After  hatching  they  remain 
for  several  hours  in  close  proximity  to  the  egg  pod  from  which  they  emerged. 
With  this  period  of  faint-heartedness  over  they  may  venture  out  for  a  few  yards 
each  day  into  the  grass,  weeds,  or  crop  neighboring  the  egg  area.  Upon  being 
disturbed  they  invariably  make  the  effort  to  hop  in  the  direction  of  their  so- 
called  nest.  Nymphs  emerging  from  eggs  on  a  ditch  bank,  if  forced  into  the 
water  will  seldom  make  the  effort  to  reach  the  other  side,  but  will  turn  back  to 
the  bank  from  which  they  were  driven.    As  development  takes  place  the  extent 


Fig.  68.    Last  two  stages  of  nymphs  of  differ- 
ential locust.    (Enlarged) 


(;rowth  and  transformations  of  insects 


55 


of  their  peregrinations  into  the  crop  is  easily  traced  by  the  shot-hole  appearance 
of  the  leaves  upon  which  they  feed.  The  tender  leaves  of  cocklebur  are 
always  preferred  by  the  grasshoppers  in  the  early  stages.  Young  Bermuda  grass 
is  also  a  favorite  food,  and  succulent  grasses  of  all  kinds  are  freely  eaten.  In 
the  third,  fourth,  and  fifth  stages,  as  grass,  weeds,  and  even  shrubs  disappear 
along  the  ditch  banks  and  bayous,  the  crops  of  corn  and  cotton  adjacent 
begin  to  show  signs  of  vigorous 
attack,  and  the  march  of  destruc- 
tion commences.  ...  A  few  hours 
before  molting  the  grasshoppers 
tend  to  congregate  and  become 
sluggish.  Molting  varies  as  to 
time,  and  slightly  as  to  manner, 
with  different  stages.  In  the  early 
stages  less  time  is  required,  and 
the  operation  occurs  on  the  ground 
or  upon  low  bunches  of  grass  and 
weeds.  Every  effort  of  the  grass- 
hoppers at  this  time  seems  to  be 
to  avoid  conspicuity,  and  in  doing 
so  spare  themselves,  in  a  man- 
ner, enmity  of  parasites.  After  the 
molting  of  the  first,  second,  and 
third  stages  it  is  not  long  before 
the  young  grasshoppers  are  suf- 
ficiently hardened  to  begin  feed- 
ing again,  but  after  the  molt  of  the 
fourth  and  fifth  stages,  particularly 
the  last  molt,  some  time  is  required 
to  extend  the  wings  and  dry  and 
harden  the  body  before  feeding  is 
reassumed.  The  last  molt  usually 
occurs  on  the  upper  and  well- 
exposed  leaves  of  corn  and  other 
plants  upon  which  they  may  be 
feeding,  though  it  is  not  uncom- 
mon for  the  grasshoppers  to  drop 
to  the  ground  during  the  maneu- 
vers of  the  process.  The  reason  for  the  selection  of  the  more  exposed  places 
for  the  last  molt  is  obvious.  The  bodies  are  large,  and  rapid  drying  protects 
them  from  fungous  diseases  which  lurk  in  the  more  shaded  and  moist  sections 
during  the  months  of  June  and  July.  The  last  prominent  habit  to  which  we 
call  attention  is  that  of  the  fully  grown  grasshoppers  to  seek  the  shade  offered 
by  the  growing  plants  during  the  hottest  part  of  the  day. 


Fig.  69.    Nymph  of  last  stage  of  differential 
locust  with  cast  skin,  on  tip  of  corn  plant 

(Authors'  illustration,  United  .States  Department 
of  -Agriculture) 


56 


ELEMENTARY  ENTOMOLOGY 


Adults.  The  hoppers  become  full  grown  about  the  first  of  July. 
The  adult  is  about  one  and  one  half  inches  long,  its  wings  expand 
two  and  one  half  inches,  and  it  is  of  a  bright  yellowish-green  color. 


Fig.  70.    The  differential  locust.    (Enlarged) 
(Authors'  illustration,  United  States  Department  of  Agriculture) 

The  head  and  thorax  are  olive-brown,  and  the  fore-wings  are  of 
much  the  same  color,  without  other  markings  than  a  brownish 
shade  at  the  base ;   the  hind-wings  are  tinged  with  green  ;   the 

hind  thighs  are  bright 
yellow,  especially  below, 
with  four  black  marks ; 
the  hind  shanks  are  yel- 
low with  black  spines 
and  a  ring  of  the  same 
color  near  the  base.  The 
adults  at  once  attack  any 
crops  available,  often 
finishing  the  destruc- 
tion of  those  injured 
by  them  as  nymphs,  but 
in  a  few  days  their  ap- 
petites seem  to  become 
somewhat  appeased  and 
they  commence  to  mate 
and  to  wander  in  search 
of  suitable  places  for 
laying  the  eggs. 

Egg  laying.  Rela- 
tively few  eggs  are  laid  in  cultivated  ground,  the  favorite  places 
being  neglected  fields  grown  up  in  grass  and  weeds,  the  edges  of 


Fig.  71.    Grasshopper  ovipositing  in  a  stump 
(Photograph  by  Weed) 


GROWTH  AND  TRANSFORMATIONS  OF  INSECTS      57 


cultivated   fields,   private   roadways,   banks  of  ditches  and  small 
streams,  and  pasture  lands.    Alfalfa  land  is  a  favorite  place  for 

oviposition,  and  alfalfa  is  often  seriously 
injured  by  this  species.  It  is  doubtless 
due  to  these  egg-laying  habits,  and  to 
the  abundance  of  food  on  uncultivated 
land,  that  this  species  always  increases 
enormously  on  land  which  has  been 
flooded  and  then  lies  idle  for  a  year  or 
two.  Most  of  the  eggs  are  laid  in  Au- 
gust and  early  September.  Each  female 
deposits  a  single  egg  mass  of  about  one 
hundred  eggs  just  beneath  the  surface 
of  the  soil.  During  this  season  the  fe- 
males may  frequently  be  found  with  their 
abdomens  thrust  deep  in  the  soil,  as  the 
process  of  egg  laying  requires  some  time. 
The  eggs  are 
arranged  in  an 
irregular  yel- 
low mass  which 
is  coated  with 
a  gluey  sub- 
stance, to  which 
the   earth   ad- 


FlG.  72.     Egg  mass   of  the 
tent  caterpillar 

(Photograph  by  Weed) 


heres  and  which  protects  them  from 
changes  of  moisture  and  temperature. 
Life  history  of  the  tent  caterpillar 
(Malacosoma  americana).  Complete  meta- 
morphosis. With  the  bursting  of  the  leaf 
buds  in  early  spring  the  tips  of  the 
branches  of  apple  and  wild  cherry  trees 
are  festooned  by  the  small,  tentlike  webs 
of  the  tent  caterpillar.  Usually  the  web  is 
formed  on  a  small  crotch,  which  gives  it 
the  tent  shape,  and  farther  out  on  the  twig 
will  be  found  the  egg  mass  from  which 


Fig.  73.  Web  of  young  tent 
caterpillars  over  the  egg  mass 

(Photograph  by  Weed) 


the  little  caterpillars  hatched,  just  before  the  leaf  buds  opened. 


5« 


ELEMENTARY  ENTOMOLOGY 


The  egg  mass  is  from  one  half  to  three  fourths  of  an  inch  long 
and  forms  a  grayish-brown,  knotlike  band  around  the  twig,  closely 
resembling  the  bark  in  color.  Each  mass  contains  from  one  hun- 
dred fifty  to  two  hundred  fifty  eggs,  placed  on  end,  packed  closely 
together,  and  covered  with  a  layer  of  light  brown,  frothy  glue,  which 
gives  a  tough,  smooth,  glistening  surface  to  the  whole  mass.  The 
eggs  are  deposited  by  the  female  moths  by   early   midsummer ; 

when  fresh  the  ^gg  mass  is 
white,  but  in  a  few  days  the 
color  darkens. 

Larva,  or  caterpillar.  Dur- 
ing late  summer  the  little  cater- 
pillars are  formed  within  the 
eggs,  but  do  not  hatch  until 
the  next  spring.  Often  they 
emerge  before  the  leaf  buds 
have  expanded  sufficiently  to 
furnish  any  food,  in  which  case 
they  satisfy  their  appetites  with 
the  glutinous  covering  of  the 
^gg  mass,  spinning  over  it  a 
thin  web.  Soon  they  are  able 
to  bore  into  the  swollen  buds, 
when  a  web  is  commenced  at 
the  nearest  crotch.  Wild  cherry 
and  apple,  which  are  often 
stripped  of  their  foliage  year 
afteryear,  are  the  favorite  foods, 
but  all  the  common  fruit  trees 
are  more  or  less  frequented,  and  sometimes  the  common  shade  trees 
are  attacked  and  occasionally  one  is  defoliated.  The  family  instinct 
is  very  strong  with  the  young  caterpillars  and  all  from  one  ^gg  mass 
cooperate  in  spinning  the  tent  which  furnishes  them  shelter  at  night 
and  during  cold  or  wet  weather.  The  tent  is  gradually  enlarged  by 
new  layers  of  silk,  which  cover  the  masses  of  excreta  in  the  lower 
layers,  the  caterpillars  living  between  the  outer  layers.  They  com- 
mence feeding  soon  after  sunrise,  but  often  retire  to  the  nest  during 
the  heat  of  the  day,  and  always  seek  its  shelter  during  cold  days  or 


Fig.  74.    Partly  formed  web  of  the  tent 
caterpillar 

(Photograph  by  Weed) 


GROWTH  AND  TRANSFORMATIONS  OF  INSECTS 


59 


when  the  sky  becomes  clouded 
and  rain  threatens.  While 
young  they  feed  together,  each 
little  caterpillar  spinning  a  fine 
strand  of  silk  wherever  it  goes, 
which  forms  a  sort  of  trail  for 
the  others.  They  become  full 
grown  in  six  or  seven  weeks, 
during  which  time  they  have 
molted  some  four  or,  excep- 
tionally, five  times,  at  intervals 
of  eight  or  nine  days,  though 
the  length  of  time  between 
molts  varies  widely  according 
to  the  food  supply  and  weather 
conditions.  After  the  fourth 
molt  the  fifth  stage  occupies 
about  two  weeks  before  the 
caterpillar  transforms  to  the 
pupa.  When  full  grown  they 
become  extremely  restless,  wan- 
der away  from  the  nest,  and  are  frequently  encountered  on  walks 
and  roadsides, 
and  feed  on  al- 
most any  plant 
found.  They 
are  now  about 
two  inches  in 
length,  deep 
black  in  color, 
thinly  covered 
with  yellowish 
hairs,  with  a 
white  stripe 
dowTi  the  mid- 
dle of  the  back. 

At    the    middle         pi^.  76.    Full-grown  tent  caterpillars  on  web.    (Reduced) 
of    the    side    of  (Photograph  by  Weed) 


Fig.  7  5.  Tent  caterpillars  about  half  grown 
on  web 

(Photograph  by  Weed) 


6o 


ELEMENTARY  ENTOMOLOGY 


each  segment  is  an  oval,  pale  blue  spot  with  a  broader,  velvety  black 
spot  adjoining  it  in  front,  giving  somewhat  the  effect  of  an  eyespot. 
Cocoon  ajtd  pupa.  Having  found  a  suitable  place  under  loose 
bark,  in  a  fence,  in  the  grass  or  rubbish  beneath  the  tree,  or  in  the 
shelter  of  some  neighboring  building,  the  caterpillar  settles  down 
and  proceeds   to   encase   itself  in  a  thin  cocoon  of  tough  white 

silk.  In  forming  the  cocoon 
the  caterpillar  rolls  its  head 
from  side  to  side,  the  silk  being 
drawn  out  from  the  lower  lip 
and  hardening  as  soon  as  it 
comes  into  contact  with  the 
air.  With  wonderful  contor- 
tions it  gradually  shapes  the 
oval  cocoon,  the  outer  part  of 
which  is  composed  of  coarse, 
loose  white  threads,  with  a 
yellowish  powder  intermixed, 
while  the  inner  layer  forms  a 
tougher,  parchmentlike  lining. 
Frequently,  when  the  caterpil- 
lars are  abundant  and  there  is 
desirable  shelter  near  the  nest, 
several  cocoons  are  formed  en 
masse. 

Exhausted  by  its  labors,  the 
caterpillar  now  becomes  quiet, 
the  body  shortens  to  about  an 
inch  long,  and,  finally,  the  skin 


Fig.  77.    Web  of  tent  caterpillars  which 
has  been  riddled  by  birds.  (Reduced) 

(Photograph  by  Weed) 


splits  down  the  back,  is  sloughed  off  into  one  end  of  the  cocoon, 
and  the  transformation  to  a  brown,  oval  object,  tho^  p?ipa,  is  accom- 
plished. The  pupa  is  about  an  inch  long,  and  the  surface  markings 
of  the  solid  shell  outline  the  legs  and  wings  of  the  adult  moth,  but 
otherwise  there  is  no  indication  of  any  relationship  to  the  larva  or 
to  the  adult,  and,  had  we  not  seen  it  emerge  from  the  larval  skin, 
it  would  be  difificult  to  believe  that  it  is  the  same  animal. 

Moth.    In  about  three  weeks  the  pupal  shell  splits  open  and  the 
adult  moth  works  its  way  out  of  one  end  of  the  cocoon.  Like  all  moths 


GROWTH  AND  TRANSFORMATIONS  OF  INSECTS     6 1 

the  adults  are  night  flyers  and  are  frequently  attracted  to  lights. 
They  are  stout-bodied,  of  a  reddish-brown  color,  with  two  nearly 


Fig.  78.    Tent  caterpillar  from  above  and  from  side.    (Slightly  enlarged) 

parallel   white  bands  extending  obliquely  across  the  fore-wings. 
The  males  are  much  smaller  and  may  be  distinguished  by  the  more 


Fig.  79.   Cocoons  of  the  tent  caterpillar.    (Natural  size) 
(After  Lowe) 

feathery  antennae.   The  sexes  soon  mate  and  the  females  deposit  the 
eggs,  which  remain  on  the  twigs  over  winter,  as  already  described. 


Fig.  So.    Female  tent  caterpillar  moth  at  rest  on  leaf.    (Slightly  enlarged) 

(After  Lowe) 


4-^^  -i.  *<--j-*vr^i*--K^Oii 


Fig.  Si.    Mourning  cloak  butterfly  depositing  eggs 
(After  \\-eed) 

62 


GROWTH  AND  TRANSFORMATIONS  OF  INSECTS     6^ 


The  life  of  the  spiny  elm  caterpillar  {Euvanessa  antiopd).  Com- 
plete metamorphosis.  What  boy  does  not  remember,  when  the  first 
warm  days  of  spring  hired  him  to  a  tramp  in  the  woods,  that  a  large, 
dark  purple,  yellow-bordered  butterfly,  usually  found  sipping  the  sap 
from  a  newly  cut  tree  stump,  was  the  first  to  greet  him  ?  It  is  one 
of  our  commonest  butterflies,  and  we  have  translated  its  German 
name  of  T^-aucrmantcl  to  "mourning  cloak  butterfly,"  though  it  is 
also  often  known  as  the  Antiopa 
butterfly,  from  its  specific  name.  It 
is  a  most  cosmopolitan  insect,  occur- 
ring throughout  North  America  as 
far  south  as  Mexico  and  Florida,  and 
is  found  over  northern  Europe  and 
in  Asia. 

Egg  laying.  Unlike  most  butter- 
flies it  hibernates  over  winter,  which 
accounts  for  its  early  and  often  some- 
what battered  appearance  in  spring.^ 
When  the  leaves  of  the  elm  and  poplar 
are  nearly  expanded,  the  female  may 
be  found  laying  her  eggs  upon  the 
twigs  of  elm,  poplar,  and  willow. 
Standing  with  wings  spread,  she  de- 
posits the  eggs  in  clusters  around  the 
twig,  as  shown  in  Fig.  8i,  <7.  In  about 
two  weeks  the  small,  blackish  cater- 
pillars emerge  through  round  holes 
eaten  out  of  the  upper  surface  of  the 
eggs,  and  crawl  to  the  nearest  leaf, 
where  they  range  themselves  side  by 
side,  with  their  heads  toward  the  margin  of  the  leaf.  Feeding  in 
this  position,  they  nibble  the  green  surface  of  the  leaf  but  leave 
the  network  of  veins  untouched. 

Laji'a,  or  caterpillar.  They  continue  to  feed  side  by  side  for 
about  a  week,  marching  in  processions  from  leaf  to  leaf  as  the  food 
supply  is  exhausted.    Each  little  caterpillar  spins  a  silken  thread 

1  We  are  indebted,  for  much  of  the  hfe  history,  to  the  account  given  by 
Dr.  C.  M.  Weed  in  Bulletin  67,  New  Hampshire  Agricultural  Experiment  Station. 


Fig.  82.    Eggs  of  the  spiny  elm 

caterpillar,    or    mourning    cloak 

butterfly,  on  willow  twig 

(Photograph  by  Weed) 


64 


ELEMENTARY  ENTOMOLOGY 


wherever  it  goes, 
so  that  the  many 
threads  soon  make 
a  fine  silken  car- 
pet, which  serves 
as  a  foothold.  At 
the  end  of  a  week 
they  molt ;  the  skin 
of  each  caterpillar 
splits  down  the 
back,  and  it  crawls 
out  with  a  new  and 
larger  skin,  which 
has  been'  forming 
beneath  the  old 
one.  The  caterpil- 
lars remain  quiet 
during  molting, 
but  they  soon  be- 
come active  again 
and  feed  with  in- 
creased voracity. 
Ever}^  week  for  the 
next  three  weeks 
this  molting  proc- 
ess is  repeated, 
the  cast  skins 
decorating  the  de- 
foliated twigs,  as 
shown  in  Fig.  84. 
As  they  grow,  the 
caterpillars  scatter 
over  the  neighbor- 
ing leaves,  but  still 
remain  in  colonies. 
Their       appetites 

Fig.  83.    The  spiny  elm  caterpillar,  or  mourning  cloak     seem     tO     increase 
butterfly.    (Slightly  reduced)  ^^  ^j^^^  g^^^,^  ^^^ 

Partly  grown  caterpillars,  chr\'salis,  empty  chrysalis,  and  adults. 
(After  Britton) 


GROWTH   AND    TRANSFORMATIONS  OF  INSECTS     65 


Fig.  84.  Twigs  denuded  by  spiny  elm  cater- 
pillars, bearing  their  cast  skins.  (Reduced) 


they  eat  more  of  the  leaf  sub- 
stance, devouring  all  but  the 
midrib  and  veins  when  half 
grown,  and,  when  larger,  leave 
only  the  midrib.  The  carpet- 
like web  which  they  spin  also 
becomes  more  evident  as  they 
gi'ow  older,  often  binding  to- 
gether the  ends  of  near-by  twigs, 
especially  where  the  caterpillars 
rest  after  feeding.  The  full- 
grown  caterpillar  is  about  two 
inches  long,  with  numerous 
branched  black  spines.  It  is 
blackish  in  color,  with  a  row 
of  red  spots  down  the  back, 
and  with  transverse  rows  of 
minute  white  spots. 

Pupa,    or   chrysalis.      The 
caterpillars  are   full  grown  in 


(Photograph  by  Weed) 

about  four  weeks.    Dr.  Weed,  in  his  interesting  account  of  this  spe- 
cies, describes  its  transformation  as  follows  : 

They  then  leave  the  tree  or  shrub  on  which 
they  have  been  feeding,  and  scatter  about,  seeking 
some  sheltered  situation.  Having  found  this,  — 
perhaps  beneath  a  stump  or  along  the  underside 
of  a  fence,  —  each  caterpillar  spins  a  web  of  silk 
along  the  surface.  It  then  entangles  the  hooked 
claws  of  its  hind  legs  (anal  prolegs)  in  this  silken 
web  and  lets  its  body  hang  vertically  with  the  head 
end  curved  upward.  It  remains  in  this  position 
for  some  hours  before  the  skin  along  the  back  just 
behind  the  head  splits  apart,  and  is  gradually 
wriggled  upward  until  it  is  finally  all  removed, 
and  there  hangs  in  place  of  the  caterpillar  a 
peculiar  object  having  no  definite  form  —  that  of 
the  chrysalis} 

In  this  quiet  chrvsalis  the  insect  is  apparently     ^^*^-  ^5-    Mourning  cloak 
1         ..         •       ^         "  ic  ^       1    •.    •.     butterfly    emerging    from 

almost  as  mert  as  a  mummv.     If  you  touch  it,  it  ,         ?■ 

■'  chr)-salis 

1  See  Fig.  S3.  (Photograph  by  Weed) 


66 


ELEMENTARY  ENTOMOLOGY 


will  wriggle  a  little,  but  otherwise  it  hangs  there  mute  and  helpless.  On  the 
inside,  however,  the  tissues  are  being  made  over  in  such  a  wonderful  way 
that  in  about  two  weeks,  from  the  mummy  case  into  which  the  caterpillar 
entered,  there  comes  a  beautiful  butterfly.  When  it  first  breaks  the  mummy 
shell  its  wings  are  very  small,  although  its  body,  "  feelers,"  and  legs  are  well 
developed.  By  means  of  the  latter  it  clings  to  the  empty  chrysalis  while  the  wings 
expand.  A  butterfly  in  this  position,  with  its  wings  nearly  expanded,  is  shown 
in  Fig.  86,  from  a  photograph  taken  from  a  living  specimen.   In  the  course  of  half 

an  hour  the  wings  become  fully  de- 
veloped, and  the  butterfly  is  likely 
to  crawl  to  some  firmer  support, 
where  it  will  rest  an  hour  or  so 
before  venturing  on  its  first  flight. 

In  New  Hampshire  there 
seems  to  be  but  a  single  gen- 
eration a  year,  the  newly 
emerged  butterflies  appear- 
ing in  July  or  August  and  dis- 
appearing during  August  and 
September,  though  they  are 
seen  occasionally  on  warm 
days  in  late  fall.  Under  the 
side  of  a  log,  beneath  the 
loose  bark  of  a  dead  tree,  in 
woodpiles,  and  in  similar  sit- 
uations the  butterflies  are  to 
be  found  during  the  winter 
lying  flat  on  the  side,  sus- 
pended under  a  culvert,  or 
in  a  hollow  tree.  Apparently 
they  are  dead,  but  if  taken 
into  a  warm  room,  they  will 
quickly  revive  and  fly  about,  and  if  given  a  little  sugar-water  for 
food,  will  live  for  some  time.  Often  in  summer  they  will  drop  on 
one  side,  motionless,  evidently  feigning  death,  and  if  lying  on  a 
background  of  dead  leaves,  are  very  difficult  to  see. 


Fig.   86.    Newly   emerged  mourning  cloak 

butterfly  hanging  to  empty  chrysalis  while 

its  wings  expand  and  harden 

(Photograph  by  Weed) 


PART  II.  THE  CLASSES  OF  INSECTS 

CHAPTER   \T 

THE  CLASSIFICATION  OF  INSECTS 

Identity  of  insects.  If  a  crop  of  potatoes  is  being  destroyed  by 
the  Colorado  potato  beetle,  it  is  at  once  recognized  as  the  cause 
of  the  injury,  and  the  method  of  control  is  known  or  may  be  ascer- 
tained from  books  or  bulletins.  In  many  cases,  however,  insects 
are  found  abundant  upon  a  crop  which  is  evidently  being  injured, 
but  the  casual  observer  may  not  be  able  to  determine  just  which 
are  responsible  for  the  injury  without  devoting  more  time  to  the 
matter  than  is  available,  or  without  more  knowledge  of  the  habits 
of  insects  than  he  possesses.  Thus,  when  a  colony  of  plant-lice  is 
found  ruining  a  crop,  there  are  usually  found  with  them  various  in- 
sects which  are  either  preying  upon  them,  as  do  the  ladybird  beetles, 
aphis-lions,  and  syrphus-fly  larvae,  or  caring  for  them,  as  do  the  ants. 
No  one  would  consider  the  ants  as  producing  the  aphides,  but  it  is 
not  at  all  uncommon  for  those  unacquainted  with  the  life  history  of 
plant-lice  to  assert  that  they  are  produced  by  the  ladybird  beetles 
or  other  insects  which  are  found  associated  with  them,  which  are 
consequently  destroyed  when  they  should  be  protected.  If  the  insect 
is  very  evidently  the  cause  of  the  injury,  but  of  unknown  iden- 
tity, it  is  of  the  utmost  importance  to  identify  it,  so  that  its  habits 
and  the  best  means  of  control  may  be  ascertained.  A  knowledge  of 
the  different  kinds  of  insects  is  thus  seen  to  be  not  only  a  matter 
of  theoretical  or  biological  knowledge,  but  of  considerable  practical 
importance. 

The  classification  of  insects  and  the  manner  in  which  they  may 
be  identified  may  be  illustrated  by  a  study  of  the  ladybird  beetles 
already  mentioned.  Upon  examining  a  ladybird  beetle,  we  at  once 
recognize  it  as  a  beetle  from  the  hard  wing-covers,  with  the  mem- 
branous hind-wings  folded  beneath  them,  and  die_bitingjTiouth^.arts. 

67 


68  ELEMENTARY  ENTOMOLOGY 

Thus  we  ascertain  that  it  belongs  to  one  of  the  several  divisions, 
called  orders,  ^nto  which  all  insects  are  divided  known  as  tlie. 
order  Cole  opt  cm.  Some  nineteen  orders  of  insects  are  now  recog- 
nized by  entomologists,  but  only  six  or  seven  are  of  any  economic 
importance.  Most  of  the  orders  are  distinguished  by  the  structure 
of  the  wings,  and  the  names  of  the  orders  usually  end  in  the  syl- 
lable//rr<^,  irom ptcjvji,  meaning  "a  wing."  A  brief  survey  of  the 
beetles  shows  that  the  order  Coleaplera  consists  of  numerous  fami- 
lies, which  are  grouped  together  according  to  the  number  of  seg- 
ments in  the  hind  tarsi.  An  examination  of  the  hind  tarsus  of  a 
ladybird  beetle  reveals  that  it  is  composed  of  but  three  segnients, 
which  is  characteristic  of  only  one  family,  the  CocciiielUdac,,  the 
family  of  the  ladybird  beetles.  A  brief  account  of  this  family  indi- 
cates that  nearly  all  of  its  members  are  predacious  upon  plant- 
lice  or  other  small  insects,  and  that  the  more  common  forms  are 
small  yellow  or  red  beetles  with  black  spots,  like  the  specimen  in 
hand.  It  is  evident,  therefore,  that  our  ladybird  beetle  is  feeding 
upon  the  plant-lice  and  is  in  no  way  responsible  for  them,  for  a 
similar  study  of  the  plant-lice  would  show  that  they  belong  to  an 
entirely  different  order  (the  Hemiptera),  which  has  sucking  mouth- 
parts  and  an  entirely  different  life  history.  We  should  also  learn 
from  the  account  of  the  Coccinellidae  that  the  little  long-legged, 
blackish,  brilliantly  marked  larvae  which  accompany  the  ladybirds 
are  the  young  stage  from  which  they  develop,  and  that  these  larvae 
also  feed  upon  the  plant-lice.  Probably  we  should  find  several 
different  kinds  of  beetles,  evidently  all  of  the  ladybird  family,  but 
differing  in  size,  shape,  and  coloration.  Should  we  desire  to  speak 
exactly  of  any  one  sort,  we  should  be  obliged  to  determine  to  what 
genus  of  the  family  it  belonged,  and  then  to  which  of  several 
species  in  that  genus.  Usually  the  amateur  will  not  be  able  to 
identify  an  insect  farther  than  to  its  family,  but  in  the  case  of 
common  forms,  especially  those  commonly  injurious,  the  illustra- 
tions or  descriptions  of  the  insect  or  its  characteristic  work  as  given 
in  textbooks,  or  the  comparison  of  the  specimen  with  those  of 
a  named  collection,  if  one  is  available,  will  make  it  possible  to 
definitely  determine  the  species. 

Scientific  names.    The  name  of  the  genus  and  species  together 
is  commonly  called  the  scientific  name,  and  is  in  Latin  and  usually 


THE  CLASSIFICATION  OF  INSECTS  69 

printed  in  italics  for  its  easy  recognition.  Scientific  names  are  a 
necessity,  because  the  common  name  of  an  insect  in  one  commu- 
nity may  often  be  applied  to  an  entirely  different  species  in  some 
other  section,  or  different  common  names  may  be  applied  to  the 
same  insect ;  and  they  are  written  in  Latin  because  that  is  under- 
stood by  scientists  in  all  countries,  and  is  common  to  them  all, 
which  is  true  of  no  other  language.  The  ladybird  beetle  in  ques- 
tion may  have  been  of  the  species  novemnotata,  meaning  nine- 
spotted,  and  of  the  genus  Coccinella,  which  is  the  typical  genus  of 
the  family.  This  name  is  written  Coccinella  novemnotata  Herbst. 
The  name  of  the  genus  is  always  placed  first  and  commenced  with 
a  capital  letter,  the  name  of  the  species  following  and  commencing 
with  a  small  letter.  Botanists  often  commence  the  specific  name 
with  a  capital  letter  if  it  is  named  for  some  person  or  country,  but 
zoologists  commence  all  specific  names  with  small  letters  to  dis- 
tinguish them  readily  from  the  generic  names.  After  the  scientific 
name  proper  is  often  placed  the  name,  or  an  abbreviation  of  the 
name,  of  the  author  who  originally  described  the  species  (as  Herbst, 
in  the  above),  for  not  infrequently  different  authors  will  use  the 
same  name  for  different  species,  which  often  results  in  endless 
confusion  when  the  name  of  the  author  who  has  described  each 
species  under  the  name  is  not  given.  Thus  the  generic  and  specific 
names  of  a  plant  or  animal  are  analogous  to  the  Christian  name 
and  surname  of  a  man,  except  that  in  the  case  of  the  latter  the 
name  applies  to  an  individual,  while  in  the  former  it  applies  to  a 
large  number  of  individuals.-  The  scientific  name  also  has  a  some- 
what analogous  significance  and  use.  Thus,  if  we  speak  of  Patrick 
O'Connor  or  Napoleon  Bonaparte,  we  at  once  think  of  the  individ- 
uals known  to  us  by  those  names.  But  the  name  also  tells  us  that 
Patrick  is  of  the  O'Connor  family,  with  their  general  characteris- 
tics, and  we  know  the  O'Connors  to  be  from  the  Emerald  Isle, 
which  we  know  to  be  inhabited  by  people  of  the  Caucasian  race, 
and,  similarly,  we  know  the  Bonapartes  to  be  Corsican.  In  the  same 
way  the  specific  name  of  a  plant  or  animal  signifies  its  relationship 
to  those  acquainted  with  the  different  sorts.  Thus  the  specific 
name  novemnotata  (or  g-notata)  at  once  signifies  that  this  particular 
species  of  beetle  has  nine  spots  and  is  a  separate  species  from  bi- 
pnnetata,  which  has  but  two  spots,  while  the  generic  name  indicates 


70  ELEMENTARY  ENTOMOLOGY 

that  it  belongs  to  the  genus  Coccinella,  to  which  this  species  and 
many  others  belong,  and  which  we  recognize  in  this  case  as  prob- 
ably belonging  to  the  family  Coccincllidac,  which  we  know  to  be  a 
family  of  predacious  beetles  of  the  order  Colcoptcra. 

Thus  animals  and  plants  are  divided  into  the  following  succes- 
sive groups  : 

Group        Examples 
Phylum  {Arthropodci) 
Class  {Insecta) 

Order  {Coleoptcra) 

Family  {Coccinellidae) 
Genus  {Coccinclla) 

Species  {iioveninotatd) 

Coccinclla  novemnotata  Herbst. 

Species.  The  exact  definition  of  a  species  has  worried  naturalists 
since  the  time  of  Linnaeus  and  is  still  under  dispute,  so  that  no 
exact  definition  will  be  attempted.  It  is  evident  that,  inasmuch  as 
it  applies  to  a  large  number  of  individuals,  and  as  we  know  that 
individuals  vary  exceedingly,  it  is  largely  a  conception  for  our 
convenience  in  designating  forms  of  life.  Inasmuch  as  we  now 
believe  that  all  forms  of  life  have  had  a  common  origin  and  have 
been  gradually  evolved  from  one  or  at  least  a  very  few  original 
ancestors  of  all  life  during  the  millions  of  years  of  the  earth's 
history,  and  as  we  know  that  species  of  plants  and  animals  are  now 
being  formed,  while  others  have  disappeared  from  the  earth,  it  is 
evident  that  the  species  now  being  formed  will  be  very  similar  to 
each  other  and  will  be  separated  with  great  difficulty,  if  at  all ; 
whereas  those  species  which  have  existed  for  a  long  period  of  time, 
and  whose  nearly  related  species  have  disappeared,  will  be  easily 
recognizable  and  form  very  distinct  species.  In  short,  it  may  be 
said  that  a  species  is  aji  aggregation  of  individuals  of  so  similar 
a  structJirc  that  they  might  all  have  been  derived  from  the  same 
parent,  wJiicJi  are  more  similar  to  each  other  tJian  to  any  other  in- 
dividuals, and  which,  ivhen  bred  together,  prodiice  progeny  of  the 
same  degree  of  likctiess,  which  zvill  also  be  fertile  and  produce  their 
kind.    The  number  of  individuals  in  a  species  and  their  distribution 


THE  CLASSIFICATION  OF  INSECTS  71 

over  the  earth  depend  upon  its  habits  and  food  supply.  Some 
species  are  exceedingly  limited  in  their  distribution,  —  as,  for  in- 
stance, the  little  butterfly  Oencis  semidca,  which  inhabits  only  the 
highest  peaks  of  the  Wliite  Mountains,  —  while  others  are  quite 
cosmopolitan,  living  in  many  distant  parts  of  the  world  and  with 
quite  different  food  habits,  an  example  being  the  bollworm  [Hcli- 
otJiis  obsolcta),  which  is  found  on  every  continent.  Some  species 
are  so  rare  that  but  one  or  two  specimens  have  ever  been  taken, 
while  others  occur  in  such  countless  myriads  as  to  become  the 
•worst  pests  of  crops. 

Genus.  As  a  species  is  composed  of  individuals  of  similar  struc- 
ture, so  a  genus  is  formed  of  a  number  of  species  having  some 
common  characteristics  which  make  them  more  nearly  related  to 
each  other  than  to  any  other  species.  In  the  same  way  genera  are 
grouped  together  into  families,  which  have  some  common  charac- 
teristics distinguishing  them  from  other  families  of  genera,  and 
families  are  likewise  grouped  into  orders.  Frequently,  various  other 
subdivisions  are  made  for  the  purpose  of  bringing  out  certain  re- 
lationships, which  are  evident  but  which  do  not  seem  to  warrant 
definite  rank.  It  should  be  observed  that  no  standard  exists  as  to 
what  structural  characters  are  sufficient  for  establishing  a  species, 
genus,  or  family,  and  that  structures  which  will  separate  species  in 
one  order  are  of  sufficient  importance  to  separate  families  in  another 
order,  this  all  depending  upon  the  constancy  and  relative  importance 
of  the  character.  Thus,  orders  are  commonly  divided  into  sub- 
orders, families  into  subfamilies,  and  genera  into  subgenera,  while 
we  recognize  varieties  and  races  of  individuals  within  a  species,  as, 
for  instance,  the  varieties  and  races  of  garden  plants  and  domestic 
animals.  In  each  case  the  subgroup  is  composed  of  a  portion  of 
the  larger  group,  which  has  some  common  characters  distinguish- 
ing it  from  the  other  subgroups  of  the  same  rank.  Such  terms  as 
sections,  divisions,  tribes,  and  series  are  also  used  in  the  same  sense. 

Inasmuch  as  some  three  hundred  thousand  species  of  insects  have 
been  described,  it  would  evidently  be  impossible  for  any  one  person, 
or  any  one  library,  to  have  all  the  descriptions  which  are  scattered 
throughout  the  scientific  books  and  journals  of  all  countries  and 
languages.  Hence  most  entomologists  acquire  a  general  knowledge 
of  the  larger  groups  and  then  make  a  special  study  of  some  one 


72  ELEMENTARY  ENTOMOLOGY 

family  or  small  portion  of  a  family,  sending  the  insects  of  other 
groups  to  specialists  of  those  groups  for  determination,  and  thus 
building  up  collections  which  they  may  use  for  the  subsequent 
determination  of  specimens  by  comparison.  The  common  families, 
and  particularly  those  of  economic  importance,  may  usually  be 
recognized  by  the  amateur,  and  the  identification  of  the  family  will 
usually  indicate  the  possible  economic  importance  of  a  given  insect, 
and  may  lead  to  its  definite  identification,  if  it  is  a  common  form. 
In  the  following  pages  we  have  endeavored  to  give  a  very  brief 
account  of  the  characteristics  of  the  more  common  orders  and 
families  of  insects.  Keys  for  their  determination  will  be  found 
in  Chapter  XX, 


CHAPTER  VII 


BRISTLETAILS  AND  SPRINGTAILS   (APTERA) 

Characteristics.  Wingless  insects  which  have  no  metamorphosis.  Mandi- 
bles and  maxillce  retracted  within  the  head,  but  used  for  biting  and  chewing 
soft  substances.  True  compound  eyes  rarely  present ;  a  group  of  simple  eyes 
on  each  side  of  head  in  some  genera.  Abdomen  sometimes  furnished  with 
rudimentary  jointed  appendages. 

This  is  a  relatively  unimportant  order  from  the  economic  stand- 
point, but  is  of  interest  from  the  fact  that  it  includes  the  most 


Fig.  87.    Silver  fish-moth  [Lepisma  saccharina).    (Enlarged) 

A  household  nuisance  and  a  good  example  of  the  bristletails.    (After  Marlatt,  United  .States 
Department  x)f  Agriculture) 

primitive  insects  now  in  existence.    The  name  Aptera  is  given  on 
account  of  the  entire  absence  of  wings,  in  consequence  of  which 

73 


74 


ELEMENTARY  ENTOMOLOGY 


-  a 


there  is  no  metamorphosis.  In  some  forms  there  are  rudimentary 
appendages  on  the  underside  of  the  abdomen,  which  are  supposed 
to  be  degenerated  abdominal  legs,  though  not  now  capable  of  being 

used  as  such.  The  order  is  divided 
into  two  distinct  suborders,  sometimes 
considered  separate  orders. 

Bristletails  {Thysanurd).  One  of  the 
commonest  bristletails  is  the  little  shiny 
fish-moth,  which  annoys  housekeepers 
by  getting  into  starched  clothes,  among 
books,  papers,  etc.  It  is  about  half  an 
inch  long,  with  long  antennae  and  three 
bristles  extending  half  the  length  of 
the  body  from  the  tip  of  the  abdomen, 
and  is  covered  with  silvery  scales  which 
glisten  as  it  darts  around  in  a  book- 
case or  drawer,  reminding  one  of  a 
fish's  scales  flashing  in  the  sunlight. 
They  are  very  soft-bodied  little  insects, 
more  abundant  in  warm  climates,  and 
feed  on  starchy  matter  or  soft  paper. 
In  some  species  of  bristletails  the  bris- 
tles have  been  modified  into  forcep- 
like  appendages.  Most  bristletails  are 
much  smaller 
than  the  fish- 
moth,  and  are 
found  beneath 
stones,  logs,  and 
loose  bark,  and 
in  similar  situ- 
ations ;  and  one  genus  {Machilis),  found  in 
many  parts  of  the  world,  has  rudimentary 
abdominal  appendages,  as  shown  in  Fig.  88. 

Springtails  {Collembold).  Every  boy  who  has  worked  in  a 
northern  maple-sugar  "  bush  "  knows  the  litde  snow  fleas,  large 
numbers  of  which  jump  around  on  the  snow  and  have  a  propen- 
sity for  getting  into  the  sap  buckets.    Other  species  are  found  on 


Fig.  88.  Underside  of  abdomen 
of  a  female  Machilis  ?na>-iii>na, 
to  show  rudimentary  limbs  {a) 
of  segments  2  to  9 ;  c,  cerci. 
(Enlarged) 

(After  Oudemans,  from  Folsom) 


Fig.  89.  The  pond-sur- 
face springtail  {^Stnyn- 
ihunis  aquatiais)  with 
spring  extended.  (Much 

enlarged) 
(After  Schott,  from  Kellogg) 


BRISTLETAILS  AND   SPRINGTAILS 


75 


the  surface  of  stagnant  pools,  in  manure  piles,  in  the  decaying 
hollows  of  trees,  in  gardens,  hotbeds,  window  boxes,  and,  in  general, 
in  moist  places  where  decaying  vegetation 
is  found.  They  are  usually  microscopic  in 
size,  from  one  tenth  to  one  twentieth  of  an 
inch  long,  but  have  an  exceedingly  inter- 
esting structure.  Projecting  forward  from 
the  underside  of  the  next  to  the  last  ab- 
dominal segment  is  a  long  abdominal  ap- 
pendage, or  spring,  by  the  extension  of 
which  the  insect  is  enabled  to  shoot  for- 
ward as  if  shot  from  a  catapult,  jumping  a 
considerable  distance.  As  the  springtails 
feed  only  on  decaying  vegetation,  they  are 
never  injurious,  unless  exceptional  num- 
bers render  them  a  nuisance.  Occasionally 
such  immense  numbers  of  small  spring- 
tails  are  found  in  manure  heaps  or  on  the 
surface  of  stagnant  pools  or  ponds  as  to  attract  attention  to  them. 
Many  of  these  little  springtails  are  prettily  colored  with  patterns 
composed  of  very  minute  scales.  For  this  reason  they  are  often 
used  as  test  objects  for  microscopes,  the  quality  of  the  lens  being 
determined  by  its  efficiency  in  revealing  the  very  fine  markings  on 
these  tiny  scales. 


Fig.  90.  Underside  of  the 
American  springtail  {Lepido- 
cyrtus  atttericaniis)  with  the 
spring  folded  underneath  the 
body.    (Much  enlarged) 

(After  Howard  and  Marlatt) 


CHAPTER  VIII 


COCKROACHES,  GRASSHOPPERS,  KATYDIDS,  AND  CRICKETS 
(ORTHOPTERA) 

Characteristics.  Insects  with  four  wings  :  the  first  pair,  more  or  less  leathery, 
not  used  for  flight,  and  forming  wing-covers  for  the  hind-wings ;  the  second 
pair  membranous,  larger,  with  numerous  veins,  and  folded  like  a  fan.  Mouth- 
parts  formed  for  biting.    Metamorphosis,  incomplete. 

The  members  of  this  order  are  among  the  best  known  of  any 
of  our  common  insects,  possibly  because  many  of  them  form  the 


Fig.  91.    The  German  roach  {Ectobia  gennmiica) 

n,  first  stage  ;  b,  second  stage  ;  c,  third  stage  ;  d,  fourth  stage  ;  e,  adult ;  /,  adult  female  with 
egg-case  ;  g,  egg-case  (enlarged)  ;  /;,  adult  with  wings  spread.    {X\\  natural  size  except  g.) 

(From  Riley) 

main  strength  of  the  insect  orchestra  of  a  drowsy  summer  even- 
ing, while  others  are  among  the  most  destructive  pests.  We  have 
already  become  fairly  well  acquainted  with  a  common  grasshopper 
(pp.  53-56)  which  forms  a  good  type  of  the  order.  The  biting 
mouth-parts,  leathery  fore-wings,  and  fanlike  hind-wings  make  the 
order  easily  distinguishable,  and  from  the  latter  characteristic  comes 
the  name  "  Orthoptera,"  from  ortJws  (straight)  2ivA  pteron  (wing), 
referring  to  the  straight-folded  wings. 

The  order  is  divided  into  six  families,  which  are  readily  distin- 
guished as  regards  both  structure  and  habits. 

76 


ORTHOPTERA 


n 


Cockroaches,  or  running  Orthoptera  {Blattidae).  The  Croton  bug, 
or  German  cockroach,  is  a  famihar  pest  in  all  eastern  cities, 
wherever  kitchens,  pantries,  and  living  rooms  are  not  kept  scru- 
pulously clean.  The  name  "Croton  bug,"  as  well  as  that  of 
"water  bug,"  comes  from  the  fact  that  it  was  introduced  into 
New  York  City  about  the  same  time  as  the  Croton  water  system, 
with  which  it  was  associated  in  the  popular  mind.  Roaches  not 
only  make  themselves  a  nuisance  by  getting  into  everything,  but 


Fig.  92.    The  oriental  roach  {Periplaneta  orientalis).    (Natural  size) 


a,  female  :  b^  male  ; 


side  view  of  female  ;  d^  half-grown  nymph.    (After  Marlatt,  United 
States  Department  o'f  Agriculture) 


often  do  serious  damage  by  gnawing  the  bindings  of  books,  eating 
off  wall  paper,  etc.  Our  common  native  species  are  larger,  almost 
black,  and  live  under  stones  and  logs  ;  they  are  of  no  economic 
importance. 

The  body  of  a  roach  is  flattened,  due  to  its  habit  of  living  in 
narrow  cracks  and  similar  out-of-the-way  places,  and  the  legs  are 
long  and  enable  it  to  run  with  remarkable  swiftness  for  so  awkward- 
looking  an  insect.  About  two  dozen  eggs  are  laid  together  in  a 
single  pod-shaped  mass,  which  is  covered  with  a  brown  cement, 
making  it  look  much  like  a  large  bean,  and  is  left  lying  in  a  crack 
or  quite  exposed. 


7« 


ELEMENTARY  ENTOMOLOGY 


The  mantids,  or  grasping  Orthoptera  (Mantidae).    Mantids  are 
found  commonly  throughout  the  southern  states,  and  form  the  only 


Fig.  93.   The  common  European  praying  mantis  (Afantis  religiosa).   (Natural  size, 

from  life) 

a,  adult  mantid  patiently  waiting  or  "  praying  "  for  its  prey ;  b,  busily  engaged  in  eating  a 
live  grasshopper.    (After  Slingerland) 

family  of  Orthoptera  which  is  strictly  predacious,  as  they  feed  en- 
tirely on  other  insects,  and  are  therefore  beneficial.  They  are  curious- 
looking  insects  and  are  called  praying  mantes,  from  the  prayerlike 


ORTHOPTERA 


79 


attitude  assumed  by  the  forelegs,  which  really,  however,  are  merely 
held  ready  to  quickly  grasp  any  unwary  insect  prey  which   may 

come  within  reach. 

Early  writers  on  natural  history 
had  many  curious  fancies  concern- 
ing this  insect,  which  are  evinced  by 
the  name  of  our  most  common  spe- 
cies, Alantis  rcligiosa  {mantis,  "a 
prophet"),  the  name  undoubtedly 
referring  to  the  pious  attitude. 


Fig.  94.    Egg  mass  of  the  praying 
mantis.    (Natural  size) 

(After  Slingerland) 

There  are  many  local  names 
for  them,  such  as  rear-horses, 
devil-horses,  etc.,  while  the 
southern  negroes  know  them 
as  mule  killers  and  other  sim- 
ilar names,  from  the  supersti- 
tion that  the  brown  saliva  from 
their  mouths  will  kill  a  mule. 
The  eggs  are  laid  in  shingled 
masses,  attached  to  a  twig  or 
weed,  and  are  coated  with  a 
hard,  gummy  covering.  The 
young,  as  well  as  the  adults, 
feed  on  insects  and  are  ex- 
tremely difficult  to  rear,  as 
they  are  rabid  cannibals,  eating 


Fig.  95.     Walking-stick  resting  on  birch 

twig,  the  leaves  of  which  were  attacked  by 

the  birch-leaf  skeletonizer 

(After  Weed) 


8o 


ELEMENTARY  ENTOMOLOGY 


each  other  with  avidity.  The 
adults  have  an  extremely 
long  prothorax,  with  a  small 
transverse  head,  and  long 
legs.  In  many  tropical 
forms  the  wings  are  bright 
gi'een  and  closely  resemble 
leaves,  thoroughly  protect- 
ing the  insect  as  it  awaits 
its  prey. 

Walking-sticks,  or  walk- 
ing Orthoptera  (Phasmidae). 
The  walking-sticks  are  aptly 
described  by  their  name ; 
so  closely  do  they  resemble 
the  twig  of  a  bush  or  tree 
that  they  are  found  with 
difficulty  and  usually  quite 
by  accident.  Only  one  spe- 
cies occurs  in  the  northern 
states,  which  feeds  upon 
the  foliage  of  forest  trees 
and  is  particularly  common 
on  hazel  and  beech,  the 
body    color    varying    from 

greenish  to  brown  according  to  the  surroundings.    In  the  tropics 

are  many  phasmids  of  large  size  and  having  wings  which  closely 

resemble  leaves  in  both  color  and  shape. 

The  large,  oval  eggs  are  dropped  loose 

upon   the   ground,  where  they  pass   the 

winter  and  hatch  the  next  summer. 
The  next  three  families  all  have  the  hind 

legs  adapted  for  jumping,  and  are  com- 
monly grouped  together  as  the  jumping 

Orthoptera.    Most^  of  the  forms  in  these 

three   families    also    have   the  ability  to 

produce   sounds   either  by  their  legs  or     j,,^  ^^    ^^^^  ^^  ^^^  ^^jl^. 

wings.  ing-stick 


Fig.  96.  A  pair  of  walking-sticks  on  a  birch  twi 
(Photograph  by  Weed) 


ORTHOPTERA 


8l 


Fig.  98. 


The  red-legged  locust. 
(Natural  size) 

(After  Riley) 


The  short-horned  grasshoppers,  or  locusts  (Acrididae).    The  word 
"grasshopper"  is  an  American  term  for  the  insects  which  in  the 

Old  World  are  called  locusts,  as  they 
are  termed  in  the  Biblical  account  of 
the  Eg}^ptian  plague  of  locusts.  The 
locusts  include  all  of  our  more  com- 
mon grasshoppers,  which  have  the 
antennae  shorter  than  the  body,  and 
a  short  ovipositor.  Man)-  of  them  are 
seriously  injurious.  Their  structure 
and  life  habits  have  alread}-  been  sufficiently  discussed  (Chaps.  V, 
XVI),  so  that  we  shall  merely  consider  a  few  of  the  more  common 
and  important  forms.  The 
most  common  throughout 
the  East  is  the  small  red- 
legged  locust  {Melanoplus 
feniur-rubrtmi)  and  the 
nearly  related  lesser  migra- 
tory locust  {Mclanoplns  at- 
lantis),  hardly  distinguish- 
able from  each  other  by  the 
casual  observer,  both  of 
which  are  abundant  in  our  pastures,  and  often  do  serious  injury  to 
grass  and  garden  crops.    One  of  the  most  common  forms  east  of 


Fig.  99.    Two-striped 
I'ii'ittafiis). 


grasshopper  [Melanopliis 
(Natural  size) 


(After  Riley) 


Fig.  100.    The  bird  grasshopper,  or  American  locust.    (Natural  size) 
(After  Riley) 

the  Rockies  is  the  Carolina  locust,  which  flies  up  along  the  roadside 
and  in  waste  places  where  it  lives.    It  closely  matches  its  surroundings 


82 


ELEMENTARY  ENTOMOLOGY 


in  color,  but  the  hind-wings  are  black,  with  a  broad  yellow  edge 
quite  conspicuous  in  flight.    Throughout  the  Mississippi  Valley 

the  differential  locust 
{Mclaiiopliis  ■diffcr- 
entialis)  is  one  of 
the  most  destructive 
forms,  being  particu- 
larly injurious  after 
floods,  when  it  multi- 
plies rapidly  on  the  un- 
cultivated land  which 
has  been  flooded.  A 
generation  ago  (i  874 
-1877),  the  crops  of 
the  western  part  of 
the  Mississippi  Val- 
ley were  utterly  de- 
stroyed for  several 
or   migratory   locusts 


Fig.  ioi.    Rocky  Mountain  locust  laying  eggs 

a,  females  ovipositing,  with  earth  cut  away  to  show  tip  of 

abdomen  placing  eggs  at  </,  and  completed  egg  mass  at  c ; 

c,  eggs.    (After  Riley) 


years  by  the  clouds  of  Rocky 
{Mclanopbis  sprctus)  which 
swooped  down  from  the 
tablelands  of  the  northwest, 
where  they  bred  and  mul- 
tiplied. Accounts  of  the 
numbers  and  voracity  of 
these  locusts  seem  almost 
incredible  to-day,  except  to 
those  who  have  seen  an 
occasional  outbreak  in  the 
northwest,  for  with  the  set- 
tling and  development  of 
the  western  plateau  they 
have  become  less  abundant, 
and  are  now  injurious  only 
in  Minnesota,  the  Dakotas, 
and  Manitoba.  In  the  mid- 
dle and  southern  states  the 
large  bird  grasshopper,  or 


Mountain 


The    Carolina    locust    {Dissoste/ra 
Carolina),  female.    (Slightly  enlarged) 

(After  Lugger) 


ORTHOPTERA 


S3 


American  Acridium  {Schistocara  avicricana),  is  common,  but 
rarely  becomes  numerous  enough  to  be  seriously  injurious.  It  is 
one  of  our  largest  species  (nearly  three  inches  long)  and  makes  as 
much  commotion  as  a  small  bird  as  it  flies  up  before  one.  In  the 
Gulf  States,  and  on  the  plains  of  the  southwest,  occur  our  two  larg- 
est species,  known  as  the  lubber  grasshopper  and  the  clumsy  locust, 
so  called  from  their  clumsy  movements.  Both  are  short-winged 
and  unable  to  fly,  but  manage  to  travel  considerable  distances. 


Fig.  103.   The  southern  lubber  grasshopper  {Dictyophom  reticulata). 
(About  natural  size) 


The  long-horned  grasshoppers  (Locustidae).  The  katydids  and 
meadow  grasshoppers  form  another  family  readily  distinguished 
by  their  slender  antennas,  which  are  much  longer  than  the  body 
and  give  the  group  the  name  "  long-horned,"  in  contrast  to  the 
short  antennas  of  the  grasshoppers,  or  locusts.  The  ovipositor  of 
the  Jemale  is  also  long  and  sword-shaped.  Unfortunately,  the 
scientific  name  of  this  family,  Locustidae,  has  the  same  root  as  the 
true  locjists,  or  grasshoppers,  with  which  they  should  not  be  con- 
fused on  that  account.  The  base  of  the  wings  of  those  males 
which  have  well-developed  wings  is  usually  constructed  for  sound 
producing,  so  that  when  the  wings  are  rubbed  together  and  set 
vibrating,  the  characteristic  note  is  made.    The  Japanese  inclose 


84 


ELEMENTARY  ENTOMOLOGY 


some  of  the  best  of  these  in- 
sect songsters  in  small  cages, 
in  much  the  same  manner 
as  we  do  song  birds.  The 
"ears,"  or  auditory  organs, 
of  the  long-horned  grass- 
hoppers, instead  of  being  in 
the  first  abdominal  segment, 
as  in  the  locusts,  are  situated 
on  the  tibia  of  the  forelegs. 
The  light  green  or  red- 
dish-brown meadow  grass- 
hoppers are  common  occu- 
pants of  our  meadows,  where 
they  may  be  heard  calling 
to  each  other  at  dusk.  The 
antennae  are  usually  very 
long,  and  often  the  ovipositor 
is  as  long  as  the  body,  being 
adapted  for  placing  the  eggs 
in  the  stems  and  roots  of 
grasses,  where  they  are  usu- 
ally laid. 

The  katydids  are  larger,  of  a  bright  green  color,  and  with  much 
broader  wings,  which  are  frequently  quite  leaflike  in  both  shape 
and  color.    The  kat\'dids  feed  mostly  in  trees,  though  some  prefer 


Fig.  104.    A  common  katydid.    (Natural  size) 
(Photograph  by  Weed) 


-Fig.  105.    A  katydid  {Microcentmm  hmrifolium)  and  its  eggs.    (Natural  size) 

(After  Riley) 


ORTHOPTERA 


85 


bushes  and  shrubs.    The  eggs  are  laid  along  the  edge  of  a  leaf  or 
along  a    stem,   slightly   shingled,   as   shown   in   Fig.    105,  being 

quite  different 
from  those  of 
any  similar  in- 
sects and  thus 
easily  recogniz- 
able. 

In  this  fam- 
ily there  are 
two  groups  of 
wingless  forms: 
the  cricketlike 
grasshoppers, 
which  are  to 
be  found  under 
stones  and  rub- 


FiG.  106.    The  western  cricket  {Anabnis  simplex),  adult 
female.    (Natural  size) 


(After  Gillette) 

bish,  particularly  in  woodlands,  and  the  shield-backed  grasshoppers, 
which  look  ver}'  much  like  crickets.  One  of  them,  known  as  the 
western  cricket  iyAuabrns),  which  is  about  one  and  one  half  inches 
long,  often  becomes  so 
abundant  in  the  northwest- 
ern states  as  to  be  ven,-  de- 
structive to  crops. 

The  crickets  {Gryllidae). 
The  common  black  or 
brownish  crickets,  with 
their  familiar  chirp,  are  well 
known  to  ever)'  one.  The 
wings  are  laid  flat  on  the 
back  when  at  rest,  instead 
of  meeting  like  a  roof  as 
in  the  grasshoppers,  the  an- 
tennae are  long,  and  the 
ovipositor  is  long,  but  cylindrical  in  section,  being  lance-shaped 
rather  than  sword-shaped  as  in  the  grasshoppers.  Our  common 
crickets  usually  feed  upon  ^•egetation,  and  very  rarely  become  inju- 
rious, though  some  are  predacious  and  at  times  are  uncompromising 


Fig.  107.    The  black  cricket,  male  and  female 
(After  J.  B.  Smith) 


86 


ELEMENTARY  ENTOMOLOGY 


cannibals.    The  egers  are  laid  in  the  ground  in  the  fall  and  hatch 


the  next  summer. 


Fig.  io8.    Female  of  GiyHiis  asshnilis,  with  inner  and  outer 
views  of  auditory  membranes  on  front  tibi^,  at  c  and  d 

(After  Marlatt,  United  States  Department  of  Agriculture) 


The  males   have  the  best-developed   musical 

apparatus  of  all 
the  orthopteran 
orchestra.  The 
principal  vein, 
which  extends 
along  the  base  of 
the  wing-cover, 
is  ridged  like  a 
file,  and  on  the 
inner  margin  of 
the  wing-cover, 
a  short  distance 
from  the  base, 
the  edge  is  hard- 
ened so  that  it 
may  be  used  as  a 

scraper,  or  rasp.  Elevating  his  wings  to  an  angle  of  forty-five  degrees, 
and  arranging  them  so  that  the 
scraper  of  one  rests  on  the  file 
of  the  other,  he  moves  them  to 
set  the  neighboring  wing  mem- 
branes into  vibration,  thus  pro- 
ducing the  shrill  call  or  the 
faint  chirp,  according  to  his 
mood. 

The  tree  crickets  are  quite 
different  from  the  common 
black  sorts  and  are  arboreal,  as 
their  name  indicates.  They  are 
of  a  creamy-white  or  light  yel- 
lowish color,  often  slightly 
tinged  with  green,  and  the  wings 
are  transparent.  The  antennas 
are  much  longer  than  the  body. 


Fig. 


109.    A  tree  cricket  {(Ecaiithns  fasci- 
atiis),  male  and  female 


(After  Lugger) 

which  is  about  half  an  inch  long,  and  the  Ovipositor  is  well  devel- 
oped.   The  wings  when  at  rest  are  usually  held  so  as  to  form  a  long 


ORTHOPTERA  8/ 

wedge  tapering  toward  the  head.  The  young  tree  crickets  are 
somewhat  beneficial,  as  they  feed  upon  plant-Hce,  but  the  adults 
do  considerably  more  injury  by  slitting  the 
twigs  of  cane  fruits,  fruit  trees,  cotton,  eto:, 
in  which  their  eggs  are  deposited,  and  beyond 
which  the  twigs  usually  die. 

One  small  group  of  crickets,  called  mole 
crickets,  are  wingless  and  live  in  the  ground, 
burrowing  here  and  there  by  means  of  the 
front  tibiae,  which  form  shovels  admirable  for 
that  purpose.  Mole  crickets  are  more  abun- 
dant in  the  South  and  Southwest,  where  they 
feed  upon  the  roots  of  plants,  but  are  very 
rarely  injurious.  In  Porto  Rico,  however,  the 
chaiiga  is  the  most  serious  insect  pest  of  the 
island,  annually  doing  one  hundred  thousand 
dollars'  worth  of  damage  to  the  staple  crops. 


Fig.    iio.       Eggs     of 

the  snowy  tree  cricket 

[CEcaiit/iiis  niveiis) 

(7,  blackberry  cane,  show- 
ing egg  punctures  ;  b,  the 
same  split,  to  show  the 
arrangement  of  the  eggs  ; 
c,  egg  very  much  en- 
larged ;  (/,  its  tip  still  more 
enlarged,     (.\fter   Kiley) 


Earwigs    (Euplexopterd). 

The  earwigs  are  nearly  re- 
lated to  the  Orthoptera, 
though  they  are  often  placed 
in  a  separate  order,  Euplex- 

optera,  which  means  "well-folded  wing,"  referring  to  the  wing, 
which  is  folded  lengthwise,  like  that  of  the  grasshopper,  and 
then    crosswise.     They   are   small    insects,    our   common   species 


Fig.  III.  Changa  {Scapteriscus  didactylus  Latr.) 

A  mole  cricket  which  is  the  most  serious  insect  pest 
in  Porto  Rico,    (.\fter  Barrett) 


88 


ELEMENTARY  ENTOMOLOGY 


being  from  one  fourth  to  one  half  an  inch  long.  The  wing-covers 
are  short  and  thick  like  those  of  some  beetles,  and  at  the  tip  of 
the  abdomen  is  a  pair  of  strong,  forceplike  appendages.    Earwigs 


Fig.  112.    An  earwig  (Forjicula  iaeniata).    (Enlarged) 

I,  male ;  2,  female ;  3,  wing  showing  fanlike  folds  and  joints  where  the 
tip  is  folded  on  the  base 

are  rare  in  the  United  States,  except  in  the  South,  and  are  not 
injurious.  The  common  name  "earwig"  arises  from  an  old  super- 
stition that  they  crawl  into  the  ears  of  sleepers  and  kill  them.  In 
the  South  they  often  fly  into  lights,  and  in  Europe  and  subtropical 
countries  they  sometimes  become  injurious. 


CHAPTER  IX 


THE  NERVE-WINGED  INSECTS,   SCORPION-FLIES,   CADDIS-FLIES, 
MAY-FLIES,  STONE-FLIES,  AND  DRAGON-FLIES 

The  earlier  naturalists  grouped  all  of  the  insects  having  four 
membranous  wings  with  numerous  fine  cross  veins,  or  nervures,  as 
they  were  then  called,  into  the  order  Neuroptera,  or  nerve-winged 
insects,  from  ncitjvn  (nerve)  ?iX\d  pteron  (wing).    Further  study  has 


Fig.  113.    The  adult  male  dobson-fly  and  its  larva,  the  hellgramite 
(After  Comstock) 

shown  that  these  insects  are  not  so  nearly  related,  and  that  they 
should  be  divided  into  several  distinct  orders,  to  exhibit  their  true 
relationship.    Few  of   them  have  any  economic  importance,  and 

89 


90 


ELEMENTARY  ENTOMOLOGY 


they  may  convenient!)-  be  considered  together  and  termed  ' '  neu- 
ropteroid  insects." 

True  Neuroptera.  In  the  true  Nciiroptera  the  wings  are  usually 
of  equal  size,  with  numerous  cross  veins,  the  mandibles  are  well 
developed,  and  the  metamorphosis  is  complete.  The  larvae  are 
carnivorous,  and  the  mandibles  are  usually  long  and  pointed.  One 
of  the  best-known  forms  is  the  large  hellgramite  {Corydalns  cor- 
mita),  whose  larvae,  known  as  dobsons,  are  the  favorite  bait  of 
the  bass  fisherman.    The  larv'ae  live  under  stones  in  swift-flowing 


Fig.  114.    Cluster  of  eggs  of  the  lace-winged  fly  {Ch>ysopa).    (Greatly  enlarged) 

(After  S.  J.  Hunter) 

streams,  where  they  feed  on  the  young  of  various  aquatic  insects. 
They  are  readily  recognized  by  the  leglike  appendages  and  a  large 
tuft  of  tracheal  gills  on  either  side  of  each  abdominal  segment 
(Fig.  113).  It  requires  nearly  three  years  for  the  larva  to  become 
full  grown,  when  it  forms  a  cell  beneath  a  stone,  or  some  object 
near  the  bank,  and  pupates,  the  adult  appearing  about  a  month 
later.  The  adults  are  readily  recognized,  as  they  have  a  wing  ex- 
panse of  from  four  to  five  and  one  half  inches  and  the  males  have 
remarkably  long  mandibles.  On  the  rocks  under  which  the  larvae 
live  the  eggs  are  laid  in  chalklike  masses  of  from  two  to  three 
thousand. 


?    o-t: 


91 


92 


ELEMENTARY  ENTCJMOLOGY 


The  aphis-lions  {CJuysopidac) 
enemies  of  the  noxious  plant-Hce. 


are  among  the  most  important 
The  lar\'as  are  small,  dark-colored, 
spindle-shaped  insects,  from 
one  fourth  to  one  third  of  an 
inch  long,  with  large,  pincer- 
like  jaws,  much  longer  than  the 
head,  with  which  they  grasp 
the  aphides.  On  the  inside 
of  each  mandible  is  a  deep 
groove,  against  which  the  max- 
illa fits,  thus  forming  a  tube 
through  which  the  juices  of  the 

(Photograph  by  Weed)  ^^^^  ^^^  SUckcd  intO  the  mOUth. 

When  full  grown,  the  larva  spins  a  small,  globular  cocoon  of 
pure  white  silk,  in  which  it  pupates.  Frequently  the  old  cocoons 
will  be  found  with  a  small,  circular  lid  which  the  adult  has  opened 


A  Myrmeleonid, 
the  ant-lion 


the  aduh  of 


Fig.  117.    The  ant-Uon 

a,  larva  of  Myrmclcon  sp.  (three  times  natural  size) ;  b,  pit  of  ant-lion,  Myrmeleon  sp.,  and 

below  a  pupal  sand-cocoon  from  which  the  adult  has  just  issued,  the  pupal  skin  remaining 

(natural  size).    (After  Kellogg) 


in  making  its  escape.  The  adults  are  about  an  inch  long,  of  a  deli- 
cate pale  green  color,  with  brown  antennas  and  finely  veined  wings, 
which  are  held  like  a  roof  over  the  back,  and  which  have  given 
them  the  name  of  "lace-winged  flies."    The  eyes  are  a  glistening 


THE  NERVE-WINGED  INSECTS 


93 


Fig.  ii8.    A  scorpion 

fly  (Paiiorpa  rttfesceiis) 

(Twice  natural  size) 

(After  Kellogg) 


gold,  from  which  they  are  sometimes  called  golden-eyes.  The  larvae 
feed  not  onlv  upon  plant-lice,  but  upon  any  soft-bodied  insects  which 
they  can  overpower,  or  on  soft  insect  eggs,  and 
will  not  infrequently  attack  their  own  species. 
The  adults  seem  fully  aware  of  these  canni- 
balistic tastes,  for  they  lay  the  little  white  eggs 
on  stalks  about  half  an  inch  high,  placing  them 
out  of  the  reach  of  the  larvae. 

In  the  undisturbed  dust  beneath  an  old  shed, 
or  beneath  cliffs,  or  along  warm  banks,  one 
will  frequently  find  the  little  funnel-shaped 
pits  of  the  ant-lions  {Myrnielcojiidac),  some- 
times locally  known  as  "  doodle  bugs."  At 
the  bottom  of  the  pit  may  be  seen  two  out- 
stretched jaws  awaiting  any  unwary  insect 
which  may  slide  down  the  crumbling  sides.  The  larvae  are  not 
unlike  those  of  the  aphis-lions  in  general  appearance,  but  have  a 
larger  abdomen  and  a  small  thorax  and  slender  legs.  The  adults  are 
dusky-colored,  with  long,  narrow,  delicate  wings.  They  are  poor 
fliers  and  are  often  attracted  to  lights  (Fig.  1 16). 

The  scorpion-flies  (order  Mecopterd)  are  readily  distinguished  by 
the  long  head,  which  is  prolonged  into  a  beak,  at  the  end  of  which 
are  the  biting  mouth-parts.  They  receive  their  common  name 
"  scorpion-flies  "  from 
the  terminal  segment 
of  the  males  of  the 
most  common  forms, 
which  is  enlarged  and 
bears  clasping  organs, 
so  that  it  looks  like  the 
fang  at  the  tip  of  the 
body  of  a  scorpion.  They  are  entirely  harmless,  howe\'er,  being  car- 
nivorous both  as  adults  and  as  larvas.  The  adults  are  most  commonly 
found  on  foliage  in  shady  places,  though  they  not  infrequently  fly  into 
lights,  while  the  larvae  look  much  like  caterpillars  and  live  in  the  soil. 
The  caddis-flies  (order  Trichoptera)  ^  have  wings  with  but  few  cross 
veins  but  more  or  less  densely  clothed  with  hairs,  thus  being  related 

^  From  t/in'x  (a  hair)  ^nd pteroii  (a  wing). 


Fig. 1 19. 


Scorpion-fl)-  larva  {Paitorpa  sp. 
times  natural  size) 

(After  Felt,  from  Kellogg) 


(Three 


94 


ELEMENTARY  ENTOMOLOGY 


to  both  the  neuropterous  insects  and  the  Lepidoptera.    The  mouth- 
parts  of  the  adults  are  quite  rudimentary.    The  hind-wings  are  often 

somewhat  larger  than  the 
fore-W'ings  and  are  then 
folded  under  them  in  repose, 
the  fore-wings  being  held 
like  a  roof  over  the  back. 
The  antennas  are  usually  very 
long  and  slender.  The  lar- 
vae are  aquatic  and  form  an 
important  item  of  fish  food. 
Some  of  them  build  most 
interesting  little  cases  from 
grains  of  gravel,  small  shells, 
bits  of  twigs,  pine  needles, 
or  whatever  rubbish  may  be 
at  hand,  lined  within  with 
silk,  which  they  carr}'  around 
with  them,  the  head  and 
thorax  projecting  out  as  they 
move  or  feed.  Every  small  pool  or  brook  harbors  some  of  these 
interesting  case  bearers,  which  will  hardly  be  distinguished  except  by 
closely  watching  the  bottom  until  they  are  seen  in  motion.  Most  of 
these  larvae  are  herbivorous,  feeding  on  whatever  vegetable  matter 
is  available,  and  look  like  small 
caterpillars.  The  caddis-worms  of 
one  group  construct  silken  nets 
across  small  rapids,  between  stones, 
or  upon  the  brink  of  little  water- 
falls, which  are  doubtless  of  serv- 
ice in  catching  the  tiny  insects 
which  float  downstream,  as  the  lar- 
vae which  make  them  are  known 
to  be  carnivorous.  When  ready  to  change  to  a  pupa,  the  caddis- 
worm  closes  up  the  entrance  to  its  case,  but  leaves  an  opening  for 
the  water  to  flow  through  so  that  the  pupa  can  breathe,  sometimes 
making  a  simple  grating  of  silk  over  the  entrance.  Upon  trans- 
forming to  the  adult  the  caddis-fly  secures  almost  immediate  use 


Fig.  I20.    Caddis-fly  larval  cases.    (Enlarged) 
(After  Furneaux) 


Fig.  121.   Adult  caddis-fly  (Goiiioiaii- 
liiis  dispcctiis  Walk).    (Enlarged) 

(After  Xeedham) 


THE  NERVE-WINGED  INSECTS  95 

of  its  wings,  as  is  highly  necessary  if  it  is  not  to  be  drowned.  Most 
insects  require  several  minutes  or  even  hours  for  the  wings  to  ex- 
pand and  harden,  but  Professor  Comstock  observed  a  caddis-fly 
which  took  flight  immediately  upon  emergence  from  the  water. 
The  adults  are  usually  gra)'ish,  brownish,  or  dusky  in  color,  marked 
with  black  or  white,  and  are  rarely  observed  except  as  they  fly 
into  lights. 

Pseudoneuroptera,  with  incomplete  metamorphosis.  All  of  the 
three  orders  just  considered  have  a  complete  metamorphosis  and  are 
more  or  less  closely  related.  The  next  three  orders  are  all  aquatic 
and  have  an  incomplete  metamorphosis,  for  which  reason  they  are 
often  grouped  together  as  false  Neuroptera  {Psciuionciiroptcrd). 

The  May-flies  {Ephemenda)  ^  are  \^  ell 
named,  for  they  are  the  most  ephemeral 
of  insects.  The  wings  are  exceedingly 
delicate  and  the  fore-wings  are  much  the 
larger,  the  hind-wings  sometimes  being 
entirely  wanting.    The  mouth-parts  of    f  ^^''^r  " 

the  adults  are  exceedingl)-  rudimentary,  fe*  i/iM^:/'  /.  ,  / 
and  they  probably  take  no  food.  The  Ml!'JAJLMm'it^ILJ:!ll 
antennse  are  short,  but  at  the  end  of   ^"'^-  '--■    ^'^^^^  ^  net-building 

,       ,  r      1    1  1  caddis-worm 

the  long,  soft  abdomen  are  two  or  three 

,  ....  ,,.,  ,  (After  Comstock) 

long,  many-jomted,  threadlike  append- 
ages, the  cerci,  which  are  quite  characteristic  of  the  May-flies.  On 
warm  nights  of  late  spring  and  early  summer  the  lights  of  towns 
near  rivers  and  lakes  are  often  darkened  by  myriads  of  May-flies. 
They  are  light  brown  or  dusky  colored,  with  wings  expanding  from 
one  to  one  and  one  half  inches,  and  with  cerci  fully  as  long.  The 
nymphs  live  at  the  bottom  of  ponds,  streams,  and  lakes,  feeding  on 
small  insects  and  vegetable  matter  in  the  ooze.  Along  either  side  of 
the  nymph's  abdomen  is  a  row  of  delicate,  platelike,  fringed  tracheal 
gills,  through  which  it  breathes,  and  at  the  tip  of  the  abdomen  are 
three  feathery  appendages.  The  legs  are  strong  and  enable  it  both 
to  walk  and  to  swim.  The  nymphs  molt  very  frequently,  there  being 
as  many  as  twenty  molts  in  some  species.  After  about  the  ninth 
molt  the  wing  pads  commence  to  appear  on  the  back,  and  become 

1  From  cphemeros  (lasting  but  a  day). 


Fig.  123.    May-flies  {Ephemera  varia  Etn.) 

/,  2,  side  and  back  views  of  nymph ;  3^  4,  side  and  back  view  of  adult  male  {Siphlurus 
alieniaius  Say);  j,  6,  side  and  back  view  of  nymph;   7,  side  view  of  adult  male.    (After 

Needham) 


96 


THE  NERVE-WINGED  INSECTS 


97 


Fig.  124.    A  stone-fly   [Pteronarcys  regalis). 
reduced) 

(After  Newport,  from  Folsom) 


(Slightly 


larger  with  each  successive  molt,  until  the  water  nymph  sheds  its 
skin  for  the  last  time,  the  gills  and  mouth-parts  are  left  behind,  and 

the  winged  May- 
fly comes  forth. 
After  flying  a 
short  distance  it 
alights  and  again 
sheds  its  skin,  a 
thin  layer  coming 
off  from  all  parts 
of  the  body,  even 
from  the  wings, 
which  process 
must  certainly  be 
the  "  exception 
which  proves  the 
rule,  "for  no  other 
insects  ever  molt 
after  becoming  winged.  The  eggs  are  now  deposited  by  the  females 
either  on  the  surface  of  the  water  or  on  stones  beneath  the  surface, 
and  in  a  few  hours,  or  at  most  in  a  day  or  two, 
the  adults  die.  The  nymphs  live  from  one 
to  three  years,  according  to  the  species,  and 
form  an  important  item  of  the  food  of  fishes, 
but  are  otherwise  of  no  economic  importance. 
The  stone-flies  (order  Plecopterd)  ^  are  quite 
similar  to  the  May-flies  in  their  general  hab- 
its, but  quite  unlike  them  in  appearance.  The 
hind-wings  are  much  larger  than  the  fore- 
wings  and  are  folded  beneath  them  in  plaits 
when  at  rest.  The  mouth-parts  of  the  adults 
are  of  the  biting  type,  but  are  often  poorly 
developed.  The  antennae  are  rather  long  and 
slender,  and  usually  there  are  two  many- 
jointed  cerci  extending  from  the  tip  of  the 
abdomen.  The  nymphs  live  beneath  stones 
in  swift-running  streams  and  are  from  one 

^  Yrom plecos  (plaited),  and  fteron  (wing).  (After  Comstock) 


Fig.  125.    A  stone-fly 
nymph 


98 


ELEMENTARY  ENTOMOLOGY 


half  to  one  and  one  half  inches  long  ;  with  their  long  legs,  and  anten- 
nae and  cerci  projecting  from  either  end,  they  have  a  very  distinctive 
appearance,  as  shown  in  Fig.  125.  Behind  each  leg  is  a  clump  of 
hairlike  tracheal  gills,  very  similar  to  those  found  on  the  dobson, 
through  which  they  breathe.  They  are  a  favorite  food  of  fishes, 
particularly  of  brook  trout,  and  make  excellent  bait.  When  full 
grown  the  nymphs  crawl  upon  rocks  or  reeds  and  transform  to  the 

adult  stone-flies,  the  old  skins 
being  frequently  found  in  such 
places.  The  adults  are  dull 
grayish  or  brownish,  the  more 
common  forms  being  from  one 
to  one  and  one  half  inches  long, 
and  are  usually  found  on  foliage 
in  shady  places  along  streams. 
They  probably  take  no  food  and 
live  only  long  enough  to  lay  the 
eggs.  Some  of  the  smaller  spe- 
cies, about  one  fourth  of  an  inch 
long,  of  a  blackish  color,  are 
often  common  on  snow  in  early 
spring,  and  frequent  windows 
at  that  time. 

The  dragon-flies  and  damsel- 
flies  (order  Odonata)  are  readily 
recognized  by  their  long,  nar- 
row, powerful  wings,  which  are 
about  equal  in  size  and  on  the 
front  margin  of  which  is  a  little 


Fig.  126. 


A    damsel-fly    (Lestes    uiicata 
Kirby),  female 

(After  Needham) 


notch  and  strong  cross  vein,  called  the  nodus .  The  mouth-parts  are 
well  developed  and  are  of  the  biting  type,  both  larvae  and  adults  being 
predacious  upon  other  insects.  The  dragon-ffies  and  damsel-flies 
are  distinguishable  both  as  adults  and  as  nymphs.  The  adult  damsel- 
fly  holds  the  wings  vertically  over  the  back  when  at  rest,  like  a  butter- 
fly ;  the  fore  and  hind  wings  are  similar  in  shape,  and  the  nymphs 
have  three  long,  leaf  like  tracheal  gills  projecting  from  the  tip  of  the 
abdomen.  The  dragon-flies  hold  their  wings  horizontally  when  at 
rest,  the  hind  wings  are  usually  much  broader  at  the  base,  and  the 


Fig.  127.    Nymph  of  a  damsel-fly 
(Lestes  sp.).   (Twice  natural  size) 

Showing   the    three   leaflike   tracheal 

gills  at  the  tip  of  the  abdomen.   (After 

Kellogg) 


Fig.  128.    Early  stages  of  nymph  of  a 
dragon-fly  (Aiiax  jiniiits  Dru.).    (All  en- 
larged) 

Showing  changes  of  color  pattern  :  A,  newly 

hatched  ;  B,  one  fourth  grown  ;    C,  one  half 

grown.    (After  Needham) 


Fig.  129.    A  dragon-fly  and  its  development 

Nymphs  feeding  at  /  and  j,  showing  extension  of  underlip  or  mask  and  the  way  prey  is 

grasped  by  it ;  2,  mature  nymph  ready  to  molt ;  4,  skin  of  nymph  from  which  the  adult  (j) 

has  emerged.    (After  Brehm) 

99 


lOO 


ELEMENTARY  ENTOMOLOGY 


nymph  has  five  converging,  spinelike  appendages  at  the  tip  of 
the  abdomen.  The  dragon-flies  are  among  the  swiftest  fliers,  dart- 
ing here  and  there  after  small  flies,  and  are  impoitant  enemies  of 
mosquitoes.  They  have  received  many  local  names,  such  as  darning 
needles,  snake  doctors,  etc.,  with  which  are  connected  many  curious 

superstitions  of  sewing  up  people's 
ears,  bringing  snakes  to  life,  etc.,  of 
which  they  are  of  course  entirely  in- 
nocent. They  are  usually  dark  colored, 
though  often  brilliantly  marked  with 
metallic  blue,  green,  and  red.  The 
damsel-flies  are  more  slender-bodied 
and  fly  lazily  about.  The  eggs  are 
laid  in  the  water  or  fastened  to  aquatic 
plants.  From  them  hatch  the  little 
long-legged  nymphs  which  may  be 
found  browsing  in  the  ooze  and  mud 
of  any  pond.  Dark-colored,  flat,  and 
spiny,  they  are  hardly  distinguishable 
from  the  debris  of  the  bottom.  They 
have  a  peculiar  underlip,  remarkably 
extensile,  with  two  .powerful  hooks 
at  the  tip,  which,  when  thrown  for- 
ward from  the  head,  grasps  the  un- 
suspecting prey.  When  drawn  in, 
the  labium  covers  the  front  of  the 
face  and  gives  the  nymph  an  exceed- 
ingly comical  appearance,  with  its 
large,  shrewd  eyes  on  either  side. 
The  nymphs  of  the  damsel-flies 
breathe  through  the  tracheal  gills  at 


Fig.  130.  A,  part  of  two  rows  of 
respiratory  folds  from  cuticular 
lining  of  rectum  of  dragon-fly 
nymph  {^Esr/t/ni).  The  shaded 
parts  are  abundantly  supplied  with 
tracheal  tubes,  as  shown  at  B,  a 
small  part  of  one  leaflet  highly 
magnified,  showing  many  fine  tra- 
cheal branches 

(Redrawn  from  Miall) 


the  tip  of  the  abdomen,  but  the 
dragon-fly  nymphs  have  a  peculiar  way  of  drawing  water  into  the 
rectum,  whose  walls  are  very  thin  and  lined  with  numerous  tra- 
chea, so  that  the  air  in  the  trachea  is  purified  through  the  wall  of 
the  rectum  as  if  it  were  a  tracheal  gill.  The  water  from  the  rectum 
may  be  ejected  forcibly,  so  as  to  drive  the  nymph  suddenly  for- 
ward.   When  full  grown  the  nymph  crawls  up  on  a  reed  or  plant 


'WwoiS^g^.iiii''""     ■'   ' 


Fu;.  131.    Development  of  a  dragon-fly  [Leiicorhinia  glacialis  Hagen) 

/,  two  nymphs  on  the  bottom  of  the  pond  ;  2,  the  empty  nymphal  skin  left  clinging  to  a 
branch  after  transformation  ;  3,  the  adult  female  ;  4,5,  back  and  side  views  of  the  adult  male 

(After  Needham) 
loi 


I02 


ELEMENTARY  ENTOMOLOGY 


and  molts  for  the  last  time,  the  adult  quickly  flying  away  and 
leaving  the  cast  skin,  which  is  often  found  intact  and  gives  an 
excellent  idea  of  the  structure  of  the  nymph,  so  remarkably  unlike 
the  adult  in  both  form  and  habit. 


Fig.  132.    Dragon-fly  [Libelhda pulchella).    (Slightly  reduced) 
A,  last  nymphal  skin  ;  i?,  adult.    (After  Folsom) 


Summary  of  the  Nerve-Winged  Insects  and  their 
Relatives 

A.  With  complete  metamorphosis : 

Order  Nenroptera.    Wings  equal ;  numerous  cross  veins. 
The  dobsons  {Sialidae).    Larvae  aquatic. 
The  aphis-lions  {Chrysopidae).    Feed  on  aphides,  etc. 
The  ant-lions  [Afyr/neleonidae).    Larvae  make  pits  in  soil. 

Order  Mecoptera.  Scorpion-flies.  Elongate  head,  and  tip  of  abdomen  fang- 
like.   Larvae  live  underground. 

Order  Trichoptera.  Caddis-flies.  Wings  with  few  cross  veins  and  clothed 
with  hairs.    Larvae  live  in  water,  many  being  case  bearers. 

B.  With  incomplete  metamorphosis  {Psendo/ieuroptera) : 

Order  Ephemerida.  May-flies.  Fore-wings  much  larger  ;  mouth-parts  rudi- 
mentary.   Nyrrlphs  aquatic. 

Order  Plecoptera.  Stone-flies.  Hind-wings  larger  and  plaited  beneath  the 
fore-wings  when  at  rest.    Nymphs  aquatic. 

Order  Odonata.  Dragon-flies  and  damsel-flies.  Wings  about  equal  in  size, 
with  a  nodus  on  the  front  margin.    Nymphs  aquatic. 


CHAPTER  X 


THE  WHITE  ANTS,   BOOK-LICE,  AND  BIRD-LICE  (PLATYPTERA) 

Characteristics.  Insects  with  two  pairs  of  delicate,  membranous  wings  equal 
or  the  hind  pair  smaller,  and  with  the  principal  veins  few  and  simple,  or  entirely 
wingless  ;  mouth-parts,  mandibulate  ;  body,  flattened  ;  prothorax,  broad  ;  meta- 
morphosis, incomplete. 

The  Platyptera  (from  platys,  "flat,"  d.ri^  ptcron,  "a  wing,"  allud- 
ing to  the  wings  of  the  white  ants,  which  lie  flat  on  the  back  when 
at  rest)  include  three  groups,  which  are  often  considered  as  separate 
orders  and  are  quite  dis- 
tinct in  appearance  and 
habits,  but  may  well  be 
placed  in  a  single  or- 
der based  upon  the  struc- 
tural characters  given 
above.  When  present 
the  wings  are  never  net- 
veined,  and  the  book-lice 
and  bird-lice  are  wing- 
less. The  body  is  usually 
flattened  and  the  pro- 
thorax  is  usually  well- 
developed  and  distinct. 

The  white  ants  {Ter- 
mitidae)  are  well-known 
inhabitants  of  fallen  logs 
and  decaying  wood,  and 
are  readily  mistaken  for 
ants  by  the  casual  observer.  The  light  yellowish  color  and  the  fact 
that  the  abdomen  is  broadly  joined  to  the  thorax,  with  no  toothed 
constriction,  as  in  the  true  ants,  easily  distinguish  them.  Though 
entirely  unrelated  to  the  true  ants,  they  have  a  very  similar  social 
organization,  with  several  distinct  castes,  of  which  only  the  so-called 

103 


'^IW'"' 


Fir,. 


a,  queen : 


White  ants,  or  termites.    (Enlarged) 

male;  r,  worker;  d,  soldier.    (.After  Jordan 
and  Kellogg) 


I04 


ELEMENTARY  ENTOMOLOGY 


kings  and  queens  are  winged.    The  wings  are  long  and  narrow, 
somewhat  leathery  in  texture,  and  are  furnished  with  numerous 

but  somewhat  indistinct 
veins,  are  about  equal  in 
size,  and  are  laid  flat  on 
the  back  when  at  rest. 
They  have  well-devel- 
oped biting  mouth-parts, 
the  mandibles  of  the  sol- 
diers projecting  well  for- 
ward of  the  huge  head. 
They  are  most  abundant 
in  the  tropics,  where 
they  are  serious  pests  of 
all  kinds  of  woodwork, 
mining  into  foundations, 
posts,  furniture,  and 
whatever  happens  in 
their  way.  The  nests  of 
the  tropical  species  are 
often  of  large  size,  form- 
ing mounds  sometimes  twelve  feet  high,  or  huge,  roundish  masses 
several  feet  thick  attached  to  trees.  But  one  species  ( Tcrvicsflavipcs) 


Fig.  134.  White  ants'  nest  on  trunk  uf  tree  (at 
arrow)  in  Cuba 

(Photograph  by  Slingerland) 


Fig.  135.    Psociis  liiieatiis.    (Much  enlarged) 
(After  J.  B.Smith) 

is  common  throughout  the  United  States ;   it  is  usually  found  in 
old  logs  and  stumps,  but  sometimes  establishes  its  nests  beneath 


THE  WHITE  ANTS,  BOOK-LICE,  AND  BIRD-LICE      105 


Fig.  136.    A  psocid  (side 

view),  showing  position  of 

wings  at  rest.    (Thirteen 

times  natural  size) 

(After  Kellogg) 


buildings,  whose  wooden  foundations  are  then  attacked  and  often 

so  mined  as  to  necessitate  their  removal.    Such  instances  are  more 

common  in  the  South,  but  even  in  the  North  porch  timbers  are 

often  attacked,  and  now  and  then  the  white  ants  invade  a  building 
^  and  thoroughly  tunnel  the  studding  and  even 

the  lathing.  The  workers  of  both  sexes  are 
wingless,  of  a  dirty  white  color,  and  busy 
themselves  in  building  their  nests,  caring  for 
the  young  termites,  and  securing  food  for 
the  whole  colony.  The  soldiers  are  also  of 
both  sexes,  wingless,  and  resemble  the  work- 
ers, except  that  the  heads  are  of  immense 
size,  being  frequently  as  large  as  the  rest  of 
the  body,  and  bear  very  strong  mandibles, 
which  form  effective  weapons.    The  kings 

and  queens  are  really  merely  fathers  and  mothers,  for  they  produce 

the  colony  but  do  not  rule  it.    In  early  summer  the  kings  (males) 

and  queens  (females)  swarm  forth  from  the  nest  and,  after  a  short 

flight,  shed  their  wings.    Individual  males 

and  females  now  mate  and  are  ready  to  start 

a  new  colony,  but  unless  they  are  found  and 

established  by  some  workers  they  perish,  and 

thus  only  few  of  them  ever  survive.    If  a 

pair  are  fortunate  enough  to  be  discovered 

by  some  workers,  they  are  provided  with 

food  and  are  imprisoned  in  a  circular  cell. 

The  queen  now  commences  to  develop  eggs, 

and  her  body  enlarges  enormously,  finally 

becoming  nothing  but  a  huge  sack,  often 

six  inches  long,  filled  with  eggs.    She  is  fed 

by  the  workers,  who  carry  away  the  eggs  and 

rear  the  young,  which  resemble  the  adults  in 

general  form.   Thus -the  domestic  economy 

of  these  colonies  is  hardly  less  interesting  than  that  of  the  true  ants. 
Book-lice.    In  neglected  libraries  or  in  old  books  which  have  been 

stored  are  to  be  found  the  tiny  book-lice  (Psocidae)  which  feed  upon 

the  paper  bindings.    They  are  exceedingly  wise-looking  little  insects 

when  examined  with  a  lens,  having  all  the  appearance  of  being 


Fig.  137.  A  wingless  book- 
louse  (.-i/n'/i' J- sp.).  (Greatly 
enlarged) 

(After  Kellogg) 


io6 


ELEMENTARY  ENTOMOLOGY 


adapted  to  their  surroundings.  Other  members  of  this  family,  called 
psocids,  are  winged  and  look  much  like  large  plant-lice.  The  wings 
are  of  a  dusky  color,  have  a  very  characteristic  venation,  and  are 
held  roof-shaped  over  the  back.  Psocids  feed  on  lichens  and  decay- 
ing wood  and  are  fre- 
quently found  in  large 
masses  on  fences  or 
tree  trunks,  where  they 
are  suspected  of  doing 
mischief,  but  they  are 
entirely  harmless  and 
need  not  be  disturbed. 
The  biting  bird-lice 
(Mallophagd)  are  curious 
looking,  wingless  para- 
sites which  infest  the 
feathers  of  poultry  and 
birds,  while  some  infest 
sheep  and  mammals. 
They  have  biting  mouth-parts  and  feed  on  feathers,  hair,  and  bits 
of  skin,  thus  differing  from  the  true  lice  (see  p.  121),  which  have 
sucking  mouth-parts  with  which  they  extract  the  blood.  The  flat- 
tened bodies  and  curiously  shaped  heads  enable  one  to  identify 
them  readily.  A  dust  bath,  with  a  frequent  thorough  cleansing  of 
the  poultry  house  by  spraying  with  kerosene  and  then  whitewash- 
ing, will  usually  prevent  serious  annoyance  to  poultry. 


Fig.  138.  Biting  lice  (A/a//o^Aaga).  (Greatly  enlarged) 

a,  turkey-louse  {Goniodes  siylifer  Nitsch)   (after  Cuvier); 

b,  the  biting  dog-louse  (Trichodectes  latus  Nitsch)   (after 
Denny).     (From   Osborn,  United    States   Department   of 

Agriculture) 


CHAPTER  XI 

THE  TRUE  BUGS,  APHIDES,  AND  SCALE  INSECTS  {HEMIPTERA) 

Characteristics.  Insects  with  four  wings,  except  in  the  parasitic  forms  ;  fore- 
wings,  thickened  at  the  base,  with  membranous  tips  and  overlapping  on  the 
back  in  the  Heteroptera,  but  entirely  membranous  and  sloping  at  the  sides  of 
the  body  in  the  suborder  Homoptera ;  mouth-parts,  suctorial ;  antennae,  few- 
jointed  ;  metamorphosis,  incomplete. 

Ordinarily  all  insects  or  small,  insectlike  animals  are  called 
bugs  by  the  uninitiated,  but  when  the  entomologist  speaks  of  a 


Fig.  139.    Fore-wings  of  Heteroptera,  showing  thickened  veins  and  arrangement 
of  veins  in  membranous  tip  characteristic  of  various  families 

/,   Capsidae ;    2,  Pyrrhocorldac ;   s,  I^ygaeidae ;    4,  Coreidae ;   j,  A^abidac ;    6,  Acantliidae 

(After  Comstock) 

bug  he  refers  to  an  insect  of  the  order  Hcmiptcra.  The  insects 
of  this  order  are  readily  recognized  by  the  strong,  pointed  suck- 
ing beak  which  extends  from  the  head  between  the  legs,  and  in 
which  are  inclosed  the  other  mouth-parts,  as  already  described  (see 
p.  17).  They  develop  with  an  incomplete  metamorphosis,  as  has 
been  described  for  the  squash-bug  (p.  50),  which  is  a  good  ex- 
ample of  one  group.  The  name  of  the  order,  Haniptera,  is  de- 
rived from  herni  (half)  and  pteron  (wing),  but  is  really  applicable 
to  only  one  suborder,  the  Heteroptera.  The  name  Heteroptera  has 
a  similar  significance,  referring  to  the  fore-wings,  which  ha\'e  the 

107 


io8 


ELEMENTARY  ENTOMOLOGY 


Fig.  140.    A  winged  pea  aphis,  illustrating  the  uni- 
form translucent,  membranous  texture  and  vena- 
tion   of   the   wings    of   the    Homoptera.     (Much 
enlarged) 


basal  half  thickened  and 
the  tips  membranous 
and  overlapping,  while 
the  hind-wings  are  en- 
tirely membranous,  so 
that  the  wings  are  unlike 
{hcicros),  and  the  beak 
arises  from  the  front  of 
the  head.  In  the  other 
principal  suborder,  the 
Homoptera,  the  wings  are 
membranous  throughout 
and  slope  at  the  sides  of 
the  body  like  a  roof,  both 
pairs  of  wings  being 
alike  {hornoios),  and  the 
beak  arises  from  the  back  of  the  head.  A  third  suborder,  the  Para- 
sita,  are  entirely  wingless,  degen- 
erate forms  which  are  parasitic 
on  man  and  other  mammals. 

Suborder  Heteroptera 

The  aquatic  bugs.  Several 
families  of  true  bugs  inhabit  our 
streams,  ponds,  and  lakes.  The 
water-boatmen  {Corisidac)  are 
from  one  fourth  to  one  half  an 
inch  long,  and  of  a  brownish 
color,  but  appear  like  glistening 
silver  as  they  dive  through  the 
water,  carrying  with  them  a  thin 
coatingof  air  which  they  breathe. 
Their  near  relatives,  the  back- 
swimmers  {Notoncctidac),  differ 
in  that  they  swim  upside  down 

,1     .    ,       1  1  .   ,  1  ,        Fig.  141.    Back-swimmers   {N'otoneda) 

on  their  backs,  which  are  shaped        ^^  ^,^  ^^^  water-boatman   {Corixa)   B. 

like  the  keel  of  a  boat  instead  of  (Slightly  enlarged) 

being  fiat.    The  water-scorpions  (After  Linville  and  Kelly) 


THE  TRUE   BUGS 


109 


{Nepidac)  are  so  called  from  the  long  tube  extending  from  the  tip 
of  the  abdomen,  which  is  thrust  to  the  surface  of  the  water  for 
breathing.    They  are  elongate  insects,   with   long  legs,   the  front 


Fig.  142.    A  water-scorpion  [Rajiatra  fitsca).    (Enlarged) 
(After  Lugger) 

pair  being  fitted  for  grasping  their  prey,  and  live  on  the  stems  of 
plants,  which  they  closely  resemble. 

The  giant  water-bugs  {Belostoniidac)  are  probably  better  known 
to  most  boys  as  electric-light  bugs, 
for  with  the  advent  of  the  arc  light 
they  have  become  very  numerous  on 
the  streets  on  warm  summer  even- 
ings. The  largest  are  over  two 
inches  long  and  can  inflict  a  pain- 
ful wound  with  their  strong  beaks, 
which  they  use  for  preying  upon 
other  insects  and  small  fish.  These 
larger  water-bugs,  as  well  as  the  back 
swimmers,  often  become  a  serious 
pest  where  the  artificial  propagation  of  fish  is  attempted.  Many  of  the 
females  fasten  their  eggs  to  their  own  backs  with  a  waterproof  glue. 

Every  one  who  has  been  fishing  knows  the  water-striders  {Hydro- 
hatidac)  which  dart  here  and  there  over  the  surface  and  suddenly 


Fig.  143.   The  undulating  back- 
swimmer    {A^ohviecta    uiiditlata). 
(Twice  natural  size) 

(After  Weed) 


B 


Fig.  144.    A,  the  giant  water-bug  or  electric-light  bug  {Belostoma  aniericaiia)  ;  B, 

the  western  water-bug  {Serphus  sp.),  male,  with  eggs  deposited  on  its  back  by 

the  female.    (Natural  size) 

(After  Kellogg) 


Fig.  145.    A  water-strider  [Hygrotrechits  remigiis  Say).    (Enlarged) 
(After  Lugger) 


Fig.  146.    The  masked  bedbug  hunter  [Opsicoetus  personatus  Linn.),  adult  and 
dust-covered  nymphs.    (Enlarged) 

(After  Brehm) 


Fig.  147.    The  big  bedbug  or  bloodsucking  cone-nose  {Co7iorhiniis  sattgjiistiga). 

(Enlarged) 

a,  /',  last  stages  of  nymphs ;   c,  d,  adults.    (After  Marlatt,  United  States  Department  of 

Agriculture) 
II I 


I  12 


ELEMENTARY  ENTOMOLOGY 


leap  for  some  unwaty  midge  or  other  small  insect.  They  usually 
occur  together  in  some  numbers,  and  some  kinds  have  been  seen 
on  the  ocean  hundreds  of  miles  from  land. 

All  of  the  aquatic  bugs  are  predacious  upon  other  insects  or  upon 
small  aquatic  animals  or  fish,  and  may  therefore  be  either  beneficial 
or  injurious,  according  to  the  nature  of  the  food. 


Fig.  14S.    The  wheel-bug  (Prionidits  cristatiis  Linn.),  eggs,  nymphs,  and  adults 
(After  Glover,  United  States  Department  of  Agriculture) 

The  predacious  bugs.  Several  terrestrial  families  are  predacious 
and  may  be  conveniently  considered  together.  The  assassin-bugs 
{Rcduviidac)  are  well  named  in  this  respect.  They  feed  on  soft- 
bodied  insects,  but  unfortunately  are  not  discriminating  in  their 
choice,  so  that  frequently  beneficial  insects  are  destroyed  in  large 
numbers.  They  are  more  common  in  the  South,  where  one  of  the 
largest  species  is  known  as  the  wheel-bug  {Arihis  cristatiis)  from 
the  large  hump,  like  a  cogwheel,  on  the  back.  In  the  North  are 
several  species,  commonly  found  around  houses,  one  of  which  is 


THE  TRUE  BUGS 


113 


known  as  the  masked  bedbug  hunter,  from  the  habit  of  the  nymph 
of  covering  itself  with  dust  and  rubbish  so  as  to  be  thoroughly  con- 
cealed as  it  waits  in  dusty  corners  for  its  prey.    This  species,  with 


Fig.  149.    Thread-legged  bug  {Emesa  longipes  De  G.) 

(After  Lugger) 


another  {Melanolcstcs  picipcs),  was  the  subject  of  considerable 
newspaper  notoriety  a  few  years  ago  as  the  kissing  bug,  since  it  not 
infrequently  attacks  the  lips  of  people  while  they  are  asleep.    The 


Fig.  150.    A  damsel-bug  (Coriscus  subcoleoptents  Kby. ) 
(After  Lugger) 

thread-legged  bugs  {Evicsidac)  are  well  described  by  their  name,  all 
of  the  legs  being  long  and  threadlike.  The  forelegs  are  fitted  for 
grasping  the  prey,  resembling  those  of  the  mantis,  and  the  anten- 
nae are  bent  so  as  to  simulate  forelegs.    They  are  sometimes  found 


114 


ELEMENTARY  ENTOMOLOGY 


Fig.  151.    Phymaia  wolfii. 

(7,  b,  side  and  back  views  ;    f,  front  leg  ;    </, 

beak.    (After  Riley,  United  .States  Department 

of  Agriculture) 


around  barns  and  sheds,  where  they  are  said  to  rob  spiders'  webs 
of  their  prey.  The  damsel-bugs  {Nabidae)  frequent  flowers  and 
vegetation,  feeding  on  any  small  insects  they  may  conquer.  The 
blond  damsel-bug  {Coriscns  ferns)  is  a  light  yellowish  color,  with 

numerous  brown  dots,  and  is 
often  taken  in  sweeping  grass 
with  a  net.  The  other  most 
common  species,  the  black 
damsel-bug  {Coriscns  snbcole- 
op trains),  receives  its  specific 
name  from  the  fact  that  at  first 
glance  it  closely  resembles  a 
beetle,  the  wings  being  mere 
rudiments  and  the  body  shin- 
ing black,  with  yellowish  legs. 
A  single  species  {Phyviata  tvolfii)  of  the  ambush-bugs  {P/iyinati- 
dae)  is  found  very  commonly  lurking  in  the  flowers  of  the  golden- 
rod.  It  is  yellowish  or  greenish  in  color,  with  a  broad  black  band 
across  the  abdomen,  and  the  front  legs  are  strongly  developed  for 
grasping,  so  that  it  is  able  to  overpower  much  larger  insects.  The 
bedbug  and  its  relatives  the  flower-bugs  {AcaniJiidac)  are  also 
predacious.  The  former  is  too  well 
known  to  need  description,  and  an- 
other similar  wingless  form  attacks 
swallows,  bats,  pigeons,  etc.  The 
flower-bugs  have  well-developed  wings 
and  lurk  in  blossoms,  where  they  at- 
tack small  insects. 

The  stink-bugs,  or  shield-shaped 
bugs  (^Pentatomidae),  are  a  large  fam- 
ily readily  distinguished  by  their 
shape,  and,  with  two  or  three  nearly 
related  but  small  and  unimportant  families,  may  be  distinguished 
from  other  terrestrial  Heteroptera  by  having  antennae  of  five  seg- 
ments instead  of  four.  The  term  "stink-bug"  is  not  definite,  for 
many  other  families  have  very  characteristic  "  buggy  "  odors,  but 
as  these  insects  frequently  attack  berries,  which  retain  their  odor,  we 
have  become  better  acquainted  with  this  disagreeable  characteristic 


Fig.  152.    Bedbug.    (Enlarged) 

,  nymph  ;    /',  adult,  with   outstretched 
beak 


THE  TRUE  BUGS 


115 


in  their  case,  —  hence  the  name.   They  have  small  heads  with  broad, 
prominent  shoulders,  and  the  large,  triangular  scutellum  occupies 


Fig.  153.    The  green  soldier-bug  (A\'zara  hllaris).    (Enlarged) 

a,  adult ;  /',  beak  ;  r,  eggs  ;  d,  single  egg  ;  e,  young  nymph  ;  /,  last  stage  of  nymph. 
(After  Chittenden,  United  States  Department  of  Agriculture) 

the  center  of  the  back  between  the  wings,  which  are  rounded  at  the 
tip  of  the  abdomen,  giving  the  whole  body  a  characteristic  shield- 
shaped  appearance.  From  an  economic  stand- 
point the  family  is  divided,  some  species  being 
predacious  upon  other  insects  and  others 
being  serious  crop  pests,  while  some  have 
both  habits,  as  circumstances  may  offer  food 
of  one  kind  or  the  other.  The  predacious 
species  are  commonly  known  as  soldier-bugs 
and  feed  mostly  upon  caterpillars.  The  com- 
mon green  soldier-bug  {Nezara  hilaris)  feeds 
upon  the  larvae  of  the  Colorado  potato-beetle, 
cotton-leaf  caterpillars,  and  other  injurious 
forms,  but  unfortunately  it  not  infrequently 
attacks  cotton  bolls,  ripening  oranges,  and 
various  fruits  and  vegetables,  doing  consider- 
able injury  by  sucking  the  juices  and  causing 
malformations.  The  spined  soldier-bug  {Po- 
dis7is  spinosiis)  is  a  common  enemy  of  leaf-eating  caterpillars,  such 
as  the  tussock  moths,  gypsy  and  brown-tail  moths,  and  of  many 
soft-bodied  grubs,  like  those  of  the  potato-beetle.  Other  species, 
like  the  harlequin  cabbage-bug  {Miaxautia  Jiistrionica),  which  is 


Fiu.  154.   Spined  soldier- 
bug    {Podisiis     spiiiosiis). 
(Enlarged) 

(After  Lugger) 


ii6 


ELEMENTARY  ENTOMOLOGY 


black  with  numerous  red  or  orange  markings  and  is  one  of  the 
most  serious  pests  of  cabbage  throughout  the  South,  feed  wholly 
on  vegetation.  Small  green  species  {TJiyanta  cnstator  -axx^  Pcnta- 
toma  sayi)  have  done  serious  injuiy  to  grain  and  forage  crops  in 
Texas  and  Colorado  in  recent  years.  The  little  Negro-bugs  of  a 
nearly  related  family  {Corimclacnidac)  are  jet-black  and  have  the 


/ 


T> 


Fig.  155.    The  harlequin  cabbage-bug 

a,  b,  adults  (natural  size)  ;  c,  side  view  of  head  with  mandibular  and  maxillary  setae  out  of 

beak ;  d,  eggs  with  newly  hatched  young  ;  e,  nymphs  ;  /,  egg  masses  with  one  egg  hatching 

and  newly  hatched  nymph  on  lower  right  mass 

scutellum  enlarged  so  that  it  covers  nearly  the  whole  abdomen 
and  gives  the  bug  the  appearance  of  a  beetle,  for  which  it  is  fre- 
quently mistaken  by  a  beginner.  They  infest  various  plants  and 
often  injure  berries  by  imparting  their  disagreeable  odor,  as  do 
the  stink-bugs. 

Plant-bugs.  The  remaining  families  of  Heteroptera  feed  entirely 
on  vegetation  and  may  for  convenience  be  grouped  together  as 
plant-bugs.  They  are  all  more  or  less  elongate  in  form,  with  slender 
legs,  and  antennae  about  half  the  length  of  the  body.   The  families 


THE  TRUE  BUGS 


117 


Fig.  156. 


Lace-bug    [Corythuca    aniiata    Say), 
adult,  eggs,  and  nymph 


(After  Comstock,  United  States  Department  of 
Agriculture) 


are  most  readily  distinguished  by  the  venation  of  the  front  wings, 
several  of  which  are  shown  in  Fig.  139,  p.  107. 

The  lace-bugs  {Tingiti- 
dae)  are  found  commonly 
on  the  leaves  of  bass- 
wood,  hawthorn,  and 
quince,  occasionally  in- 
juring the  latter.  "  One 
glance  at  the  fine  white 
meshes  that  cover  the 
wings  and  spined  thorax 
is  sufficient,"  says  Pro- 
fessor Comstock,  "to  dis- 
tinguish them  from  all 
other  insects,  for  these  are 
the  only  ones  that  are  clothed  from  head  to  foot  in  fine  white 
Brussels  net."  They  are  small  insects,  about  the  size  of  plant-lice, 
and  suck  the  juices  of  the 
leaves.  The  eggs  are  cov- 
ered with  a  sticky  sub- 
stance and  look  like  fungi 
on  the  undersurface  of 
the  leaf. 

The  leaf -bugs  (Capsidae) 
form  the  largest  family  of 
Heteroptera,  having  over 
two  hundred  fifty  species 
in  this  country.  One  of 
the  most  common  species 
is  the  tarnished  plant-bug 
{Lygus  pj'atensis).  This 
is  yellowish-  or  greenish- 
brown  in  color,  about 
one  fourth  of  an  inch 
long  (Fig.  157),  and  at- 
tacks a  great  variety  of  plants,  being  injurious  to  nursery  trees, 
sugar  beets,  strawberries,  and  various  vegetables  and  flowering 
plants,  causing  the  tips  of  plants  like  the  dahlia  and  potato  to 


Fig.  157.  Tarnished  plant-bug.  (About  four  times 
natural  size) 

(7,  bj  c,  d,  four  stages  of  nymphs ;  e,  adult  bug.    (After 
Forbes  and  Chittenden) 


ii8 


ELEMENTARY  ENTOMOLOGY 


wither  beyond  the  point  where  the  httle  bug  has  inserted  its  beak. 
The  four-hned   leaf-bug  {Poecilocapsiis  lineatus)  is  yellowish  or 


P'iG.  158.    The  four-lined  leaf-bug 

«,  adult  (enlarged) ;  b,  adult  (natural  size)  ;  c,  single  egg  (greatly  enlarged) ;  d,  lengthwise 
section  of  stem,  showing  eggs  in  position  (enlarged).    (After  Slingerland) 

greenish,  with  four  black  stripes  (Fig.  158),  and  is  often  a  serious 
enemy  of  currants,  laying  its  eggs  in  the  stalks  and  thus  killing 
the  tips.    The  cotton  leaf-bug  is  found  throughout  the  country  on 


Fig.  159.    Cotton  leaf-bug  [Calocoris  rapidiis) 

a,  mature  bug ;  b,  young  nymph  ;  c,  fourth  stage  of  nymph  ;  d,  fifth  stage  of  nymph 
(Authors'  illustration,  United  States  Department  of  Agriculture) 


THE  TRUE   BUGS 


119 


various  flowers  and  is  sometimes  an  enemy  of  the  sugar  beet,  but 
in  the  South  it  is  best  known  for  causing  the  cotton  squares  to  drop 
and  producing  black  spots  and  distortions  of  the  bolls.    It  is  dark 


Fig.  160.    A  stilt-bug  {Jalysus  sphiosiis  Say).    (Enlarged) 
(After  Lugger) 

brown,  with  a  narrow  yellow  border,  the  prothorax  being  )ellow  and 
red  with  two  black  spots.  Nearly  related  is  the  red-bug  family  [Py?-- 
rJiocoridac),  named  after  the  red-bug,  or  cotton-stainer  {Dysdcrcus 


Fig.  161.    The  chinch-bug.    (Much  enlarged) 

Adult  at  left ;   a,  l>,  eggs  ;  c,  newly  hatched  nymph  :  </,  its  tarsus  :  c,  f.  g,  second,  third,  and 

fourth  stages  of  nymph  ;  //,  leg  of  adult ;  J,  tarsus  of  same  ;  /,  proboscis,  or  beak.    Hair  lines 

indicate  natural  size.    (After  Webster  and  Riley) 

snturclhis),  an  insect  of  a  reddish  color,  with  pale  yellow  stripes, 
with  habits  very  similar  to  the  one  last  mentioned,  staining  the  cot- 
ton where  it  punctures  the  bolls.  Though  common,  it  is  by  no 
means  a  serious  pest  of  cotton,  but  is  often  injurious  to  ripening 


I20 


ELEMENTARY  ENTOMOLOGY 


oranges.  The  family  is  a  small  one  of  relatively  large,  bright-colored 
bugs,  with  few  species  in  the  North.  The  stilt-bugs  {Bcrytidac) 
are  well  named  from  their  long,  stiltlike  legs.  They  resemble  the 
thread-legged  bugs  in  this  respect,  but  are  much  smaller,  being 

only  about  one  third  of 
an  inch  long.  Only  two 
species  are  known  in  the 
United  States ;  these  fre- 
quent the  undergrowth 
of  woodland  and  pas- 
tures. The  chinch-bug 
is  the  best-known  exam- 
ple of  one  of  the  larg- 
est families  {Lygaeidae), 
with  nearly  two  hundred 
species  in  this  country.  The  chinch-bug  is  about  one  sixth  of  an 
inch  long,  of  a  jet-black  color,  with  the  fore-wings  white  with  a 
distinct  triangular  black  spot  at  the  middle  of  the  outer  margin. 


Fig. 1 6 


The  false  chinch-bug  {Xysiiis  ericae  Schill.) 
(Much  enlarged) 

a,  injured  leaf;  /',  last  stage  of  nymph  ;  c,  adult. 
(After  Riley) 


Fig.  163.    a,  the  northern  leaf-footed  plant-bug  [Leptoglossiis  oppositus);   b,  the 
banded  leaf -footed  plant-bug  {Leptoglossiis  p/iyiloptts).    (Twice  natural  size) 

(After  Chittenden,  United  States  Department  of  Agriculture) 

The  young  stages  are  red  but  become  gray  or  blackish  as  they 
grow  older.  It  is  found  in  all  parts  of  the  United  States,  but  has 
been  most  seriously  injurious  in  the  Mississippi  Valley. 


I'HK  TRUK   BUGS 


121 


The  squash-bug  and  its  relatives  form  another  large  family 
{Coreidac)  of  some  two  hundred  species,  of  which  the  common 
squash-bug  {Anasa  tristis),  which  we  have  already  considered 
(p.  50),  is  the  best-known  example.  In  the  middle  and  southern 
states  there  are  several  nearly  related  species 
which  have  the  hind  tibia  flattened  and  ex- 
panded somewhat  like  a  leaf,  and  are  known 
as  leaf-footed  plant-bugs.  The  box-elder  bug 
{Lcptocoris  trivittatiis)  is  a  common  species 
throughout  the  Mississippi  Valley  and  Great 
Plains,  where  it  is  a  serious  enemy  of  the 
box  elder,  which  is  planted  largely  for  shade. 
It  is  blackish,  with  three  bright  red  lines  on  the 
prothorax,  and  with  fore-wings  having  edges 
and  veins  of  a  dingy  red. 


Fig.    164.      Box-elder 

bug    [Leptocon's    iriv it- 
tat  us).    (Twice  natural 
size) 


(After  Kellogg) 


Suborder  Parasita 

As  their  name  indicates,  the  members  of 
this  suborder  are  parasites  upon  man  and  other 
mammals,  being  commonly  known  as  lice.  They  may  well  be  called 
the  true  lice,  or  sucking  lice,  to  distinguish  them  from  the  bird-lice 
{Mallophagd),  plant- 
lice  {Aphididac),  and 
other  insects  com- 
monly called  lice. 
They  are  small,  soft- 
bodied,  wingless  in- 
sects, with  a  stout, 
unsegmented  beak, 
either  without  eyes  or 
with  only  simple  eyes, 
and  the  tarsi  bear  but 
a  single  claw,  all  of 
these  characters  indi- 
cating a  degenerate 
group.  The  head-louse  infests  the  hair  of  man,  and  the  body- 
louse,  or  grayback,  as  soldiers  term  it,  lives  in  and  lays  its  eggs  in 
the  seams  of  clothing.    The  general  appearance,  greatly  enlarged, 


Fig.  165. 


Sucking  lice  affecting  man. 
enlarged) 


(Cireatly 


(?,    crab-louse    {PtJiiniis    iiigitbialis    Leach)  ;     /',    head-louse 

{Pediiidiis  capitis  De  Ci.).   (^7,  after  Denny  ;  b,  after  Packard  ; 

from  Osbom,  United  States  Department  of  Agriculture) 


122 


ELEMENTARY  ENTOMOLOGY 


of  these  vermin  is  shown  in  Fig.  165.    Similar  species  infest  horses, 
cattle,  and  other  domestic  animals,  as  well  as  many  wild  mammals. 

Suborder  Homoptera 

The  cicadas  {Cicadidae).  The  common  dog-day  harvest-fly 
(Fig.  166)  is  the  best  known  example  of  this  interesting  family; 
and  although  we  seldom  see  it,  we  are  made  aware  of  its  presence 
on  a  hot  summer  day  by  the  shrill  calls  answered  back  and  forth 
from  the  tree  tops.  It  is  black  and  green  in  color,  more  or  less 
powdered  with  white  beneath.    The  most  remarkable  member  of 


Fig.  166.    Dog-day  harvest-fly  {Cicada  iibicen),  female 
(After  Lugger) 

the  family  is  the  periodical  cicada,  often  improperly  called  the 
seventeen-year  locust,  from  its  habit  of  appearing  in  immense 
numbers  every  seventeen  years.  It  is  of  course  entirely  unrelated 
to  the  true  locusts,  or  grasshoppers.  The  adults  lay  their  eggs  in 
the  twigs  of  trees,  often  seriously  injuring  young  fruit  trees,  as  the 
twigs  or  stems  die  beyond  the  point  of  the  egg  puncture.  The 
nymphs  drop  to  the  ground  upon  hatching  and,  burrowing  into 
the  earth,  feed  upon  the  roots  of  trees  for  sixteen  years.  The 
seventeenth  year  they  emerge  in  immense  numbers  within  a  few 
days,  crawl  up  the  trunks  of  trees,  fences,  buildings,  etc.,  and  trans- 
form to  the  adults,  which  are  blackish,  with  orange  markings  on 
the  wings.  For  the  next  few  weeks  the  air  is  filled  with  their 
shrill  cries,  and  soon  many  affected  trees  turn  brown  as  a  result  of 


Fig.  167.    Periodical  cicada 

<7,  adult;  l>,  young  nymph   (enlarged);  c,  cast  skin  of  full-grown  nymph;  d,  side  view  of 

female  to  show  beak,  c,  and  ovipositor,  /.    (Natural  size  except  i>.)    (After  Marlatt  and  Riley, 

United  States  Department  of  Agriculture) 


Fig.  168.    Buffalo  tree-hopper  and  twig  of  apple  tree  showing  eggs  and  adult 

Adult  (enlarged)  at  left ;  a,  adult  (natural  size)  ;  i,  recent  egg  punctures ;  <r,  bark  reversed 

with  eggs  in  position;  d,  single  row  of  eggs  (enlarged);  e,  wounds  of  two  or  three  years' 

standing  on  older  limbs,    (.^fter  Marlatt,  United  States  Department  of  Agriculture) 


123 


124 


ELEMENTARY  ENTOMOLOGY 


Fig.  169.    The  bittersweet  tree-hopper  {Enchoiopa 

binotata  Say).    Adult  (side  and  bacii  views)  and  egg 

mass.    (Much  enlarged) 

(.•\fter  Lugger) 


their  egg  laying.   The  different  broods  have  been  carefully  mapped, 

so  that  it  is  possible  to  foretell  the  appearance  in  any  given  locality 

where  the  insect  occurs. ^ 

Plant-hoppers.    The  next  three  families  may  be  grouped  together 

under  the  term  "plant-hoppers,"  as  they  jump  off  suddenly  when 

disturbed.  They  are 
small  insects,  usually 
not  over  one  fourth 
of  an  inch  long,  and 
suck  the  sap  from  the 
leaves  and  stems  of 
their  food  plants.  The 
tree-hoppers  {Alcin- 
bracidac)  have  been 
called  the  ' '  brownie 
insects,"  for  their  bi- 
zarre shapes  are  often 

comically  grotesque.    The  prothorax  is  prolonged  back  over  the 

abdomen  and  is  often  produced  forward  or  up- 
ward into  horns  or  crests,  as  shown  in  Fig.  169. 

One  of  the  most  common  species  is  the  buffalo 

tree-hopper  {Ceresa  bnbalns),  which  lays  its  eggs 

in  the  stems  of  weeds  and  young  fruit  trees, 

causing  large  knotty  scars  on  the  twigs.  Another 

small  brown  species  {Enchcnopa    binotata)    is 

common  on  the  bittersweet  vine,  the  projecting 

prothorax  looking  exactly  like  a  thorn  on  the 

stem.    Few  species  of  this  family  are  sufificiently 

numerous  to  do  serious  damage. 

-     Here  and  there  on  weeds,   grass,  and  tree 

foliage  will  be  found  a  little  mass  of  froth,  within 

which  may  be  found  a  small  nymph,  which  is 

busily  pumping  the  sap  out  of  the  plant,  thus 

causing  the  froth  which  was  formerly  supposed 

to  be  voided  by  tree  frogs  and  was  termed  ' '  frog 

spittle,"  —  hence    the    insects    of    this    family 


Fu;.  170.  Mass  of  spit- 
tle   produced  by  the 
nymph  of  a  frog-hop- 
per, or  spittle-insect 


1  See  Bulletin  No.  7/,  Bureau  of  Entomology,  United  States  Department  of 
Agriculture,  for  a  very  complete  and  interesting  account. 


THE  TRUE  BUGS 


125 


(Ccrcopidac)  arc  called  "frog-hoppers "  or  "spittle-insects."  Within 
this  frothy  mass  the  little  n)'mph  molts  and  grows  and  finally 
forms  a  little  clear  space  about  its  bod)-,  around  which  the  foam  dries, 
forming  a  little  chamber  within  which  it  transforms  to  the  adult. 
Though  very  commonh'  in  evidence,  few  of  this  family  are  injurious. 
The  leaf-hoppers  {Jassidae)  are  among  the  most  abundant  of  the 
Homoptera.  Take  a  net  and  sweep  back  and  forth  in  any  meadow 
and  you  will  secure  hundreds  of 
them,  Professor  Herbert  Osborn 
having  estimated  that  frequently 
over  a  million  live  on  an  acre  of 
grassland.  They  are  more  slender 
than  the  two  preceding  families, 
from  an  eighth  to  a  fourth  of  an 
inch  long,  and  of  a  brownish, 
green,  or  red  color,  the  green  and 
red  often  being  arranged  in  stripes, 
giving  a  very  striking  coloration. 
The  grape  leaf-hopper  ( Typhlo- 
cyba  comes),  commonly  called  the 
grape  thrips  (although  it  is  not  a 
true  thrips),  is  one. of  the  most 
serious  enemies  of  the  vine.  In 
late  summer  the  foliage  will  often 
be  brown  as  a  result  of  their  work, 
and  a  slight  jar  will  cause  them 
to  fly  off  in  clouds.  They  are 
small  yellowish  hoppers,  scarcely 
an  eighth  of  an  inch  long  and 
strikingly  marked  with  red  and  black.  A  yellowish-green  species, 
the  rose  leaf-hopper  {Einpoasca  jvsac),  often  does  considerable 
injur}^  to  rose  foliage,  and  a  similar  one,  the  apple  leaf-hopper 
{Einpoasca  iiiali),  is  found  on  the  apple  and  frequently  becomes  a 
serious  pest  in  the  nursery.  The  presence  of  these  leaf-hoppers 
is  always  indicated  by  the  numerous  white  cast  skins  of  the  nymphs 
clinging  to  the  undersides  of  the  leaves.  Leaf-hoppers  fly  to  lights 
in  large  numbers.  The}'  hibernate  as  adults,  and  the  eggs  are 
usually  laid  just  beneath  the  surface  of  the  leaf  of  the  food  plant. 


Fig.  171.   Aphrophora  ^-iiotata  Say, 
a  common  frog-hopper 

(.A.fter  Lugger) 


Fig.  172.    Three  cotton  leaf-hoppers,  commonly  called  "sharpshooters." 
(Much  enlarged) 

a,  Aitlacizes  irroraia  :  b,  Oncomctopia  iimlata  :  c,  Oncometopia  lateralis.    (Authors'  illustra- 
tion, United  States  Department  of  Agriculture) 


Fig.  173.    Grape  leaf-hoppers.    (Much  enlarged) 

a  and  b  are  female  and  male  of  typical  comes  variety  ;  c  represents  the  v'ltis  variety  ;  </,  newly 

hatched  nymph  ;  <?,  last  stage  nymph  ;  /,  injured  leaf ;  g,  cast  skins.    (After  Marlatt,  United 

States  Department  of  Agriculture) 

126 


THE  TRUE  BUGS  I  27 

The  psyllas,  or  jumping  plant-lice  (Psyllidae),  look  much  like 
miniature  cicadas,  but  are  more  nearly  related  to  the  true  plant-lice, 
exuding  sweet  hone}'-de\v  like  the  plant-lice  but  differing  from  them 
in  being  very  agile  in  the  adult  stage,  giving  a  quick  jump  with  their 
strong  hind  legs  and  flying  off  at  the  slightest  disturbance,  whereas 
the  true  plant-lice  are  exceedingly  sluggish.  The  best-known  example 
is  the  pear  psylla  {Psylla pyricola),  the  adult  of  which  (Fig.  174,  a) 
is  not  over  a  tenth  of  an  inch  long  but  which  occurs  in  such  enormous 
numbers  that  it  sometimes  entirely  ruins  large  pear  orchards  by 
sucking  the  sap  from  the  foliage.  It  has  been  most  injurious  in 
the  Middle  Atlantic  States.    It  exudes  a  large  amount  of  honey-dew, 


Fig.  174.    The  pear  psylla.    (Greatly  enlarged,  in  different  proportions) 
rt,  adult ;  /'.  full-grown  nymph  from  above  ;  r,  egg.    (After  -Slingerland) 

which  covers  the  foliage  and  bark,  on  which  grows  a  sooty  black 
fungus  which  is  a  good  indication  of  the  presence  of  the  pest. 

The  plant-lice,  or  aphides  (Aphididae),  are  the  most  abundant  and 
possibly  the  most  destructive  family  of  all  the  Hemiptera.  Florists 
commonly  call  them  green-flies,  which  term  may  refer  to  several 
species.  Usually  they  are  not  over  a  tenth  of  an  inch  long,  and 
the  wingless  forms  are  more  or  less  pear-shaped,  with  long  legs 
and  antennae,  and  the  common  forms  have  two  tubes  projecting 
from  the  abdomen,  called  honey-tubes.  The  vast  amount  of 
injur)^  done  by  them  is  chiefly  due  to  their  remarkably  rapid  power 
of  reproduction.  During  the  summer  the  females  will  give  birth 
to  from  fifty  to  seventy-five  young  during  a  week  or  two,  which 
will  become  full  grown  in  from  one  to  two  weeks.    All  of  these 


128 


ELEMENTARY  ENTOMOLOGY 


prove  to  be  females,  there  usually  being  no  males  during  the 
summer,  and  each  gives  birth  to  a  similar  number  of  young,  the 
egg  stage  being  passed  within  the  body  of  the  female  and  the  young 

being  born  alive.  Thus 
generation  after  gener- 
ation is  produced,  and  a 
simple  arithmetical  cal- 
culation will  show  that 
the  resulting  progeny 
must  soon  become  suf- 
ficiently numerous  to 
entirely  destroy  the  veg- 
etation from  which  the 
myriad  little  beaks  are 
pumping  out  the  sap. 
In  the  fall  true  males  and  females  usually  appear,  and  eggs  are 
laid  which  hatch  in  the  early  spring.  Most  species  are  wingless 
until  the  food  supply  commences  to  get  short,  when  the  next  gen- 
eration develops  wings  and  migrates  to  new  food  plants.  Many 
species  have  winged  generations  in  the  spring  and   fall,   which 


Fig.  175.    Wingless  female  pea  aphis  and  newly 
born  young.    (Enlarged) 


Fig.  176.    Apple  aphis,  last  stage  nymphs  of  winged  females  on  undersurface  of 

apple  leaf 

migrate  to  and  from  the  summer  food  plants  to  others  upon  which 
they  feed  in  fall  and  spring,  and  upon  which  the  winter  eggs  are 
deposited.    Many  plant-lice  exude  an  abundance  of  a  sweet  liquid 


THE  TRUE  P3UGS 


129 


Fig.  177.  Aphis 

eggs    on    twig. 

(Natural  size) 

(Aiter  Weed) 


called  honey-dew,  and  are  constantly  attended  by  ants,  which 
eagerly  devour  it.  In  the  case  of  several  species  the  ants  care  for 
them  almost  as  if  they  were  their  domestic  animals, 
and  very  commonly  ants  are  responsible  for  carrying 
the  aphides  from  one  plant  to  another  as  the  food 
supply  becomes  exhausted,  as  in  the  case  of  the  melon 
aphis  and  the  strawberry  root-louse.  Among  the  more 
common  species  are  the  common  green  apple  aphis 
{Aphis pomi),  the  cabbage  aphis,  the  pea  aphis,  which 
often  destroys  entire  crops  of  garden  peas  in  the  At- 
lantic states,  the  green  bug  {Toxoptcra  grajitiuinn), 
which  has  recently  been  so 
injurious  to  grain  crops  in 
the  southwest,  the  melon 
aphis,  the  rose  aphis,  the 
chrysanthemum  aphis, 
and  a  host  of  others.  The 
foliage  of  almost  every 
plant  is  attacked  by  one 
or  more  species,  and  many  of  the  most  in- 
jurious attack  the  roots,  as  the  corn  root- 
aphis  {Aphis  maidi-radicis),  which  is  one 
of  the  most  serious  corn  pests  in  the  Miss- 
issippi Valley.  The  grape  phylloxera,  an 
American  species  attacking  the  roots  of 
the  grape,  was  imported  into  Europe  and 
soon  became  the  worst  enemy  of  the  vine 
in  France,  where  it  has  caused  the  loss 
of  millions  of  dollars.  Several  species 
exude  a  cottony  mass  of  wax  over  the 
body,  so  that  they  appear  like  a  mold. 
Among  these  the  woolly  apple  aphis  is 
often  seen  on  the  leaves  and  on  wounds 
and  scars  on  the  bark  of  apple  trees,  and 
a  similar  species  covers  the  twigs  of  alder 
as  if  they  were  wound  with  cotton. 

The  scale  insects  (Coccidae).    Some  of  the  worst  insect  pests  of 
the  fruit  orchard  belong  to  the  scale  insects,  which  are  so  peculiar 


Fig.  178.    Tip  of  dock  stem 
covered  with  black  aphides 


Fig.  179.    Melon  aphis.    (Greatly  enlarged) 

a,  winged  female  ;  a' ,  enlarged  antenna  of  same  ;  ab,  dark  female  (side  view),  sucking  juice 

from  leaf ;  b^  young  nymph ;  c,  last  stage  of  nymph  of  winged  form ;  d,  wingless  female. 

(After  Chittenden,  United  States  Department  of  Agriculture) 


Fig.  180.    Mealy-bug  (Dactylopius  longifiUs),  female  and  winged  male.    (Enlarged) 

(After  Comstock,  United  States  Department  of  Agriculture) 

130 


THE  TRUE  BUGS 


131 


in  form  that  they  would  not  be  readily  recognized  as  insects,  were 
their  complicated  life  histories  not  known.    Three  quite  distinct 


Fig.  181.    The  cochineal  insect 
(7,  on  cactus;  ^,  male;  c,  female  (enlarged).    (From  Riverside  Natural  History) 

groups  may  be  readily  distinguished.  The  mealy-bugs  are  fre- 
quently found  on  greenhouse  plants,  and  are  so  named  from  their 
mealy  covering  of  wax  and  the  numerous  white,  waxy  filaments 


Fig.  1S2.    The  peach  lecanium,  or  terrapin  scale 

Adults  at  left  (much  enlarged  and  natural  size) ;  young  at  center  and  unfertilized  female  at 
right  (much  enlarged).    (After  Howard,  United  States  Department  of  Agriculture) 

which  are  given  off  from  their  bodies.  They  are  from  an  eighth  to 
a  quarter  of  an  inch  long,  and  move  about  slowly  over  the  plant, 
retaining  their  les^s  througrhout  life.    The  soft  scales  include  those 


I  ^2 


ELEMENTARY  ENTOMOLOGY 


of  the  genus  Lccaniuvi  and  their 
near  relatives,  and  are  known  as 
Lecaniums.  They  are  usually  of 
a  brownish  color,  quite  strongly 
convex  (often  ridged),  and  are 
soft  and  easily  crushed,  —  hence 
the  name.  The  upper  surface 
of  the  female  gradually  hardens, 
and   upon    ma- 


FlG.  183.      The   hemispherical  scale 
{Lecaniuni  hemisphaericum  Targ.) 

a,  scales  on  olive  (natural  size);  />,  three 
female  scales  (considerably  enlarged);  c, 
female  scale  lifted  from  leaf,  showing  mass 
of  eggs  (enlarged).  (After  Marlatt,  United 
States  Department  of  Agriculture) 


eggs 
neath   it. 


turity  she  dies 
and  the  old  skin 
forms  the  scale 
which  covers  the 
laid  be- 
The 

Lecaniums  occur  upon  various  greenhouse  plants 
such  as  crotons,  upon  the  peach  and  plum, 
and  upon  citrous  fniits.  The 
cottony  maple  scale  is  a 
species  common  on  maple 
shade  trees  and  gives  off 
a  mass  of  cottony  wax  in 
which  the  eggs  are  laid. 

The  armored  scales  are 
much  smaller,  flat,  circular, 


Fig.   185.     The    oyster- 
shell  scale  on  poplar  twig 
(Photograph  by  Weed) 


Fig.  184.    The  col- 
or elongate  in  outline,  and    tony  maple   scale 

1    J  ^  (Enlarged) 

mclude  our  most  common 

^  ^  ,  ,  .  ,  (After  Comstock) 

species.  Upon  hatching,  the 
young  scale  insect  crawls  about  for  an  hour  or 
two  and  then  settles  down,  inserts  its  beak  in 
the  leaf  or  bark,  and  henceforth  the  females 
remain  in  the  same  place.  Soon  waxy  fila- 
ments commence  to  exude  from  the  body, 
which  mat  down  into  a  small  scale  covering 
the  insect.  When  the  skin  is  molted,  it  is 
added  to  the  center  or  one  end  of  the  scale, 
which  is  gradually  enlarged  and  assumes  a 
characteristic  shape.   With  the  first  molts  the 


THE  TRUE   BUGS 


133 


female  loses  her  legs  and  eyes,  and  the  body  becomes  a  mere  mass 
of  yellowish  protoplasm  with  long,  threadlike  mouth-parts  and  a 
characteristic  fringe  of  plates 
and  hairs  at  the  tip  of  the  abdo- 
men, by  which  the  species  is 
principally  distinguished.  They 
are  named  armored  scales  be- 
cause the  scales  of  this  group 
are  mere  coverings  and  form  no 
part  of  the  insect.  The  scales 
of  the  males  are  much  smaller 
than  those  of  the  females,  and 
after  the  second  molt  the  male 
goes  into  a  true  pupa  stage 
(otherwise  the  Hemiptera  have 
incomplete  metamorphosis),  the 
legs,  wings,  and  antennae  being 
outlined,  and  with  the  next  molt 
the  adult  male  emerges  from  the  scale  and  flies,  to  fertilize  the  fe- 
male.   The  adult  males  of  all  the  Coccidae  have  but  a  single  pair  of 


Fig.  186.   Female  San  Jose  scale,  mature 

female  insect  removed  from  beneath  it. 

(Greatly  enlarged) 

(After  Alwood) 


Fig.  187.    n,  winged  male  San  Jose  scale  (much  enlarged);  A,  young  scale  insect 
(enlarged  125  times) 

(After  Alwood) 

wings,  like  the  flies  {Diptera),  and  bear  long  antennae  and  usually 
one  or  two  long  processes  from  the  tip  of  the  abdomen.  They  are 
very  small  whitish  or  yellowish  insects,  and  usually  fly  at  night,  so 


134 


ELEMENTARY  ENTOMOLOGY 


that  they  are  rarely  seen  unless  reared  from  the  scales.  Among  the 
most  common  of  the  armored  scales  are  the  oyster-shell  bark-louse  (so 
called  on  account  of  the  resemblance  of  the  brown  scale  to  an  oyster 


Fig.  i88.    Peach  twigs  infested  with  San  Jose  scale.    (Much  enlarged) 

At  left,  large  mature  female  and  small  young  scales  are  clustered  in  a  groove  of  the 

twig.   At  right  is  shown  a  large  female  scale  with  the  scale  proper  raised,  showing  the 

insect  beneath.    (After  Britton) 

shell),  which  is  common  on  apple  and  several  shade  trees  ;  the  San 
Jose  scale,  possibly  the  most  serious  pest  of  fruit  trees ;  the  rose  scale, 
common  on  roses,  raspberries,  and  blackberry  canes ;  and  the  various 
fiat  scales  found  on  palms  and  other  greenhouse  and  house  plants. 


THE  TRUE  BUGS 
Summary  of  the  Hemiptera 

I.   Suborder  Hctcropiera.    Wings  unlike. 
I .  Aquatic  bugs. 

The  water-boatmen  [Corisidae). 
The  back-swimmers  {Notonectidae). 
The  water-scorpions  {Xepidae). 
The  giant  water-bugs  (Belosto)nidae). 
The  water-striders  {Hydrobatidae). 

2.  Predacious  bugs. 

The  assassin-bugs  {Reduviidae). 

The  long-legged  bugs  [E/nesidae). 

The  damsel-bugs  [A'cTbidae). 

The  ambush-bugs  {Phymatidae). 

The  bedbugs  {Acanthidae). 

The  stink-bugs,  or  shield-shaped  bugs  {Pe/ifiifotfiidae). 

3.  Plant  bugs. 

The  stink-bugs,  or  shield-shaped  bugs  {Pentato>/iidae). 

The  lace-bugs  (Tingitidae). 

The  leaf-bugs  {Capsidae). 

The  red-bugs  {Pyrr/iocoridae). 

The  stilt-bugs  {Berytidae). 

The  chinch-bugs  {Lygeidae). 

The  squash-bugs  (Coreidae). 

II.   Suborder  Parasita.    Wingless  parasites  of  animals. 

III.  Sxxhorder  Ho7nopfera.    Wings  alike,  translucent. 

1.  The.  cicdidz.?,  (Cicadidae). 

2.  The  plant-hoppers. 

The  tree-hoppers  {Menibracidae). 

The  frog-hoppers,  or  spittle  insects  {Cercopidae). 

The  leaf-hoppers  {Jassidae). 

3.  The  psyllas,  or  jumping  plant-lice  {Psyllidae). 

4.  The  plant-lice  {Aphididae). 

5.  The  scale  insects  (Coccidae). 


135 


CHAPTER   XII 

THE  BEETLES  (COLEOPTERA) 

Characteristics.  Fore-wings,  horny  or  leathery,  forming  wing-covers  (elytra), 
which  meet  in  a  straight  line  down  the  back ;  hind-wings,  membranous,  tips 
folded  back  under  the  wing-covers  when  at  rest ;  mandibulate  mouth-parts ; 
metamorphosis,  complete. 

The  hard  wing-covers  of  this  order  are  so  characteristic  that  a 
beetle  is  commonly  recognized  as  such,  and  they  have  given  the 


Fig.  189.    A  water-scavenger  beetle  with  wing-covers  and  wings  expanded 
as  when  in  flight.    (Natural  size) 

(After  Folsom) 

order  its  scientific  name,  from  coleos  (a  sheath)  and  pteron  (a 
wing).  The  beetles  form  one  of  the  largest  orders,  with  over  twelve 
thousand  species  in  America  north  of  Mexico,  belonging  to  some 
eighty  families,  only  the  most  common  of  which  will  be  mentioned. 
They  have  a  complete  metamorphosis,  the  larvae  being  commonly 
called  grubs,  and  the  pupae  are  usually  found  either  in  the  ground 

136 


THE  BEETLES 


137 


or  in  the  foodstuff  of  the  larvae.  Both  larvae  and  adults  have  biting 
mouth-parts,  similar  to  those  of  the  grasshopper,  the  structure  vary- 
ing with  the  food  habits  of  the  species. 

The  families  of  beetles  are  divided  into  several  groups,  based 
largely  on  the  structure  of  the  tarsi  and  antennae,  which  aid  the 
student  in  their  identification.  The  order  is  primarily  divided  into 
the  typical  beetles  {Coleoptcni  gcnuina),  in  which  the  head  is  nor- 
mal, and  the  snout-beetles  {RJiynchopJwra),  in  which  the  head  is 
prolonged  into  a  snout,  or  beak,  at  the  tip  of 
which  are  the  biting  mouth-parts. 

The  Typical  Beetles  {Cqleoptera 
GENU IX a) 

Four  principal  sections  of  the  families  of 
typical  beetles  are  distinguished  by  the  num- 
ber of  segments  in  the  tarsi. 

L  BEETLES   WITH    FIVE-JOINTED   TARSI 
[PENTAMERA) 

The  first  section  is  distinguished  by  all  of 
the  tarsi  being  composed  of  five  segments, 
and  is  divided  into  four  tribes  according  to 
the  structure  of  the  antennae. 


"    TJie  Carnivorous  Beetles  {Adephagd) 

The  carnivorous,  or  predacious,  beetles 
include  several  families,  all  of  which  feed 
upon  other  insects  and  are  therefore  bene- 
ficial. The  antennae  are  threadlike,  with  dis- 
tinct, cylindrical  segments. 


Fig.  190.  A  tiger-beetle 
{Cicindela limbata).  (Hair 
line  shows  natural  size) 

(After  Bruner) 


The  tiger-beetles  (Cicindelidae).  Along  sandy  paths,  roadsides,  rail- 
road embankments,  and  in  similar  open,  sunny  spots,  the  tiger- 
beetles  fly  up  and  dart  swiftly  ahead  as  one  approaches.  They 
are  swift  runners  and  stalk  their  prey  on  foot.  Most  of  our  com- 
mon species  are  either  a  brilliant,  metallic  green  or  a  brownish- 
bronze,  banded  or  spotted  with  yellow.  The  larvae  live  in  little 
burrows  in  the  ground,  the  head  appearing  at  the  opening  so  that 
the  eyes  command  the  surroundings,  and  any  unwar)'  passing  insect 
may  be  seized  with  the  strong  jaws.  Toward  the  tip  of  the  abdomen 


ivS 


ELEMENTARY  ENTOMOLOGY 


•«^vt.. 


is  a  decided  hump,  and  surmounting  it  are  strong,  curved  spines 
which  serve  as  an  anchor,  so  that  a  captured  insect  cannot  drag  the 

lar\^a   from    its   burrow.     The   vo- 
racity of  these  beetles  makes  the 
name  "tiger-beetle"  fitting,  but  un- 
fortunately they  are  of  little  bene- 
fit to  the  farmer,  as  they  do  not 
frequent  cultivated   fields,  and  though   they   de- 
stroy many  insects,  but  few  of  them  are  of  any 
economic  importance.   The  brilliant  green  species 
are  favorites  of  collectors,  and  one  must  be  some- 
thing of  a  sportsman  to  secure  many  of  them,  so 
readily  do  they  fly.    Like  many  other  active  insects 
they  may  often  be  easily  caught  towards  sundown. 
Ground-beetles.     Upon   turning   over   a    stone 
or  a  log,  one  frequently   sees   small,    flat,   black 
beetles  scurrying  away,  which  belong  to  the  fam- 
ily of  ground-beetles  (Carabidac).    Their  name  is 
Fig.  iqi.  A  tiger"        ^         o  \ 

beetle  and  its  lar-     indicative  of  their  habits,  as  their  long  legs  fit 

va   in  its  burrow. _ 

(Natural  size) 

(After  Linville  and 

Kelly) 

them  for  chas- 
ing rapidly  over 
the  ground  in 
pursuit  of  small 
insects,  though 
some  of  them 
ascend  trees  in 
search  of  cater- 
pillars. This  is 
a  large  family, 
which  has  some 
twelve  hundred 

'^^  Fig.  192.    A  ground-beetle   [Calosoma   sp.)   feeding  on  a 

country,  and  as  cutworm  ;  below,  a  species  of  Ca7-abus 

both  larvae  and  (After  Brehm) 


THE  BEETLES 


139 


adults  feed  on  many  of  our  most  noxious  insects,  ground-beetles 
must  rank  among  the  farmer's  best  friends.  The  larvae  live  in  the 
ground,  or  in  places  similar  to  those  of  the  adults,  and  are  also  pre- 
dacious. The  larvae  are  elongate,  the  body  tapering  slightly  at  either 
end,  with  the  strong  jaws  projecting  in  front  and  two  bristly  append- 
ages at  the  tip  of  the  abdomen.  Our  largest  common  species  is  the 
searcher  {Caloscwm  scrutator),  whose  wing-covers  are  a  beautiful 
green  or  violet,  mar- 
gined with  reddish,  and 
whose  body  is  marked 
with  blue,  gold,  green, 
and  copper.  It  fre- 
quently ascends  trees  in 
search  of  caterpillars, 
and,  with  nearly  related 
species,  often  does  good 
work  in  destroying  large 
numbers  of  them  when 
they  become  overabun- 
dant. A  European  spe- 
cies of  this  genus  has 
recently  been  imported 
into  Massachusetts  to 
prey  upon  the  gypsy- 
moth  caterpillars.  A 
medium-sized  species 
with  yellowish-red  head 
and  thorax  and  bright 

blue  wing-covers  {Lcbia      (After  Howard,  United  States  Department  of  Agriculture) 

graiiciis)  (Fig.  195)  has 

made  a  name  for  itself  as  an  enemy  of  the  eggs  and  larv^  of  the 
Colorado  potato-beetle.  Our  most  common  species  are  from  one 
fourth  to  one  half  an  inch  long,  either  shining  black  or  with 
greenish,  bluish,  or  coppery  reflections,  and  veiy  frequently  fly  to 
lights  in  considerable  numbers.  Their  larvae  feed  on  soft-bodied 
insects  which  go  into  the  ground  to  pupate,  such  as  the  plum 
curculio  and  others,  while  the  larger  ones  are  among  the  most 
important  enemies  of  cutworms  and  various  caterpillars. 


Fig.   193.     European  ground-beetle  {Calosoma 

sycGphattia)    imported  to    prey    on    the    gypsy 

and  brown-tail  moths 


I40 


ELEMENTARY  ENTOMOLOGY 


The  predacious  diving-beetles  (Dytisci- 
dae)  are  to  be  found  in  any  pond,  where 
they  may  be  seen  suspended  at  the  sur- 
face of  the  water  with  the  tip  of  the  abdo- 
men thrust  up  so  that  air  may  be  drawn 
in  under  the  elytra,  or  diving  here  and 
there  after  their  prey,  which  consists  of 
any  insects  that  they  can  overpower,  small 
aquatic  animals,  and  occasionally  small 
fish.  The  largest  species  are  about  an 
inch  long,  while  the  commoner  ones  are 
one  half  or  three  fourths  as  large  and  are 
brownish-black,  often  marked  with  dull 
yellow.  The  hind  legs  are  long,  flattened, 
and  fringed  with  hairs, 
forming  admirable  swim- 
ming organs.  The  larvae  are  elongate,  spindle- 
shaped  grubs,  with  strong,  ferocious-looking  jaws, 
with  which  they  grasp  and  suck  out  the  juices  of 
their  prey,  which  has  given  them  the  name  of 
water-tigers. 

Whirligig-beetles.  Every  pool  is  the  home  of 
a  school  of  the  well-known  whirligig-beetles  {Gyri- 
nidac),  which  chase  each  other  over  the  surface, 
where  they  feed  on  small  insects  which  fall  into 
the  water.  They  are  usually  much  smaller  than  the  last-named 
family,  are  oval  in  shape,  much  flattened,  of  a  jet-black  color,  and 


Fig.    194.     A    ground-beetle 

(Calosoiiia  calichiin).   (Natural 
size) 


Fig.  195.  Lebia 
grandis,  an  im- 
portant enemy  of 
the  potato-beetle 
(Enlarged) 


Fig.  196.    A  common  ground-beetle  {Harpahis  caliginosus).  (Enlarged) 
A,  its  larva;  B,  head  of  larva,  showing  mouth-parts.    (After  Riley) 


THE  BEETLES 


141 


are  readily  recognizable  by  the  front  margin  of  the  head  extending 
across  the  eyes  so  that  there  seems  to  be  a  pair  of  eyes  on  both 
the  upper  and  the  under  surface. 

The  Club-Homed  Beetles  {Clavieoi-Jiia) 

The  antennae  of  the  beetles  of  this  tribe  are  either 
'^  gradually  or  abruptly  thickened  toward  the  tip  so  as 

to  form  a  club.  The 
common  families 
either  live  as  scav- 
engers or  feed  on 
stored  products, 
but  there  is  a  large 
series  of  small  fam- 
ilies with  the  most 
varied  habits,  al- 
though not  many 
include  species  of 
serious  economic 
importance. 

The  water-scavenger  beetles  (Hydrophilidae)  closely  resemble  the 
predacious  diving-beetles,  but  are  more  convex  above  and  more 
flattened  below,  have  more  highly  polished  wing-covers,  and  have 


Fig.  197.    A  predacious  diving-beetle  (Dytiscus  sp.). 
(Natural  size) 

(r,  larva,  or  "water-tiger";  h,  pupa;  c,  adult.    (After  Kellogg) 


Fig.  198.    Whirligig-beetles  {Uyr/in.!\u  ].    1  Xaiural  sizci 
(.\fter  Linville  and  Kelly) 


antennae  that  are  decidedly  clubbed,  though  often  concealed  beneath 
the  head.  They  feed  on  decaying  animal  and  plant  tissues,  though 
they  not  uncommonly  catch  small   insects,  and  the  larvae  feed 


14: 


ELEMENTARY  ENTOMOLOGY 


entirely  on  insects,  snails,  tadpoles,  etc.    Both  middle  and  hind 
legs  are  developed  for  swimming  and  are  used  alternately. 


'ucA/k^.:^~-^:^^=l^ 


Fig.  199.    Water-scavenger  beetles  [Ilydrophilits  sp.),  larva,  and  peculiar 
egg  mass  on  leaf 

(After  Brehm) 

Carrion-beetles  (Silphidae).    Wherever  a  dead  animal  has. been 
left  exposed,  the  carrion-  or  burying-beetles  may  be  found  feeding 

upon' it.  The  more  com- 
mon carrion-beetles  of  the 
genus  SilpJia  are  of  a 
broad,  oval  shape,  much 
flattened, with  small  heads, 
and  feed  beneath  the  car- 
rion. The  burying-beetles 
{Xccropliorus)  are  much 
larger,  from  an  inch  to  an 
inch  and  a  half  long,  with 
thick,  stout,  rectangular 
bodies,  and  with  large 
,    ,,,       ,  ,     heads.  The  common  spe- 

A  burying-beetle  [Aecrophonis  sp.).  ,  ,      ,  •   , 

(Slightly  enlarged)  cies  are  blackish,  marked 

(After  Linviiie  and  Kelly)  with  dull  red.  Their  name 


Fig.  200. 


THE  BEETLES 


143 


Fig.  201.  A  carrion-beetle 
(Silpka  iiovaboraceiisis)  and 
(One  and  one  half  times 
natural  size) 

(After  Kellogg) 


larv; 


is  derived  from  their  habit  of  excavating  beneath  dead  animals, 
which  they  gradually  drop  beneath  the  surface  and  then  cover 
with  soil.  Both  adults  and  larvae  feed  on  decomposing  animals 
and  are  among  the  chief  natural  agents  for  their  sanitary  disposal, 
though  some  species  are  predacious  and  others  feed  on  decaying 

fungi.  The  larvae  are  black,  flattened, 
with  the  segments  sharply  marked,  and 
are  found  with  the  adults. 

The  rove-beetles  (Staphylinidae).  The 
rove-beetles  are  readily  recognized  by 
the  very  short  wing-covers,  usually  not 
o\'er  a  third  of  the  length  of  the  abdo- 
men. Most  species  are  very  small,  but 
the  more  common  ones  are  from  half  an 
inch  to  an  inch  long,  with  narrow,  parallel- 
sided  bodies.  They  run  about  swiftly  and 
when  disturbed  curl  up  the  abdomen  as 
if  to  sting.  The  larger  common  species  are  found  with  the  SilpJiidac 
feeding  on  carrion  or  decaying  organic  matter,  being  commonly 
found  in  dump  heaps,  while  the  smaller 
species  feed  on  pollen,  fungi,  or  small 
insects. 

Cucujidae.  The  saw-toothed  grain-beetle 
{Silvamis  siirinaniensis),  which  is  one  of 
our  commonest  grain  pests,  is  a  good  ex- 
ample of  the  small  family  Citcujidac.  It 
is  a  small,  flat  beetle,  an  eighth  of  an 
inch  long,  and  readily  distinguished 
from  other  small  grain  insects  by  the  ser- 
rated edges  of  the  thorax.  It  feeds  also  on  all  sorts  of  fruits,  seeds, 
and  dry  pantry  stores,  as  do  the  little  whitish  larvae.  The  other  com- 
mon species  are  much-flattened  beetles  which  live  beneath  bark  and 
feed  upon  small  insects  and  fungi.  One  of  these  {Cticnjtis  clavipes) 
is  a  bright  red,  with  eyes  and  antennae  black  and  tibiae  and  tarsi 
dark,  and  is  readily  recognized  by  the  thin  body. 

Larder-beetles.  Every  housewife  knows  that  she  must  be  on  the 
lookout  for  the  small  carpet-beetle,  often  called  the  buffalo-moth 
{AiitJircnus  scropJinlai-ia),   and   for   the   larder-beetle    {Dcrmestes 


Fig.  202. 


A  rove-beetle  and 

its  larva 


144 


ELEMENTARY  ENTOMOLOGY 


lardarius),  in  stored  meats  or  feathers.  These  are  typical  represent- 
atives of  a  small  family,  Dcrmestidac,  of  oval,  plump  beetles,  the 
largest  being  about  one  third  of  an  inch  long.  They  are  usually 
grayish,  brownish,  or  blackish,  marked  with  colors  due  to  minute 
scales  with  which  the  body  is  covered.    All  of  this  family  feed  on 


Fig.  203.  The  saw-toothed  grain-beetle.  (Much  enlarged) 
a,  adult;  /',  pupa;  <-,  larva.    (After  Chittenden,  United  States  Department  of  Agriculture) 

dried  animal  substances,  and  some  of  the  smaller  species  are  par- 
ticularly noxious  to  the  entomologist,  as  they  are  the  worst  pests 
which  he  has  to  combat  in  his  collection  cases. 


TJic  Saxv-Horncd  Beetles  {Serrieornia) 

The  tribe  of  saw-horned  beetles  includes  several  families  of  quite 
different  habits,  which  are  very  loosely  related  by  all  having  serrated 
antennae,  the  segments  of  the  antennae  being  prolonged  inward  so 
as  to  give  the  whole  antenna  a  saw-toothed  or  serrate  appearance. 

Click-beetles.  Every  boy  knows  the  long  click-beetles,  or  snap- 
ping beetles  {Elateridae),  which,  when  placed  on  their  backs,  will 
flop  up  in  the  air  with  a  decided  click,  or  snap.  They  are  flat, 
elongate  beetles,  the  commoner  forms  being  about  three  fourths 
of  an  inch  long  and  of  a  dull  brown  color.  The  head  is  small  and 
the  posterior  angles  of  the  thorax  are  much  prolonged,  giving  it 


Fig.  204.    The  carpet-beetle,  or  buffalo-moth.    (Enlarged) 
a,  larva  ;  /',  pupa  in  lar\-al  skin  ;  f,  pupa  from  below  ;  d,  adult.    (After  Kiley) 


Fig.  205.    The  larder-beetle.    (Enlarged) 
a,  lar\-a  ;  /',  pupa  ;  <■,  adult  beetle,   (.\fter  Howard,  United  States  Department  of  .Agriculture) 


14s 


146 


ELEMENTARY  ENTOMOLOGY 


a  characteristic  shield  shape.    The  larvae  are  known  as  wire-worms 

and  are  among  the  worst  pests  of  corn  and  small  grains.    Some 

wire-worms  live  under  bark  and  in 
decaying  wood,  the  adult  of  one  of 
these  being  the  common  eyed  elater 
{Alans  ociilatjis),  a  large  species  an 
inch  and  a  half  long,  blackish,  flecked 
with  gray,  with  two  large,  velvet-black, 
white-rimmed  eyespots  on  the  thorax, 
which  give  it  a  very  wise  appearance. 
The  metallic  wood-borers  {Bupres- 
tidae)  have  much  the  same  general 
shape  as  the  click-beetles,  but  the 
tips  of  the  elytra  are  more  pointed, 
the  beetles  are 
unable  to  spring, 
and  their  colors 
are  metallic.  The 
adults  are  medi- 
um-sized beetles, 
often  found  on 
flowers   or   bark, 

and  do  no  harm  as  adults.     The  larvae  are 

flat,  whitish   grubs  with   small,   brown  heads 


Fig.  206.   The  eyed  elater  (Ahn/ 
ocitlatus.)    (Slightly  enlarged) 

(After  Linville  and  Kelly) 


Fig.  207.    a,  beetle  of  wheat  wire-worm  [Agriotes  7na>icHs) ;  /',  beetle  of  Drasterius 
elegans  ;  c,  larva  of  same.    (Much  enlarged) 

(After  Forbes) 


THE  BEETLES 


147 


and  with  the  prothorax  greatly  widened,  giving  them  the  name 
"flat-headed  borers,"  which  is  also  often  applied  to  the  family. 

They  are  to  be  found  beneath 
bark,  making  irregular  cham- 
bers in  the  sapwood  and  in  the 
inside  of  the  bark.  Some  feed 
only  on  dead  or  dying  tim- 
ber, while  others,  like  the 
flat-headed  apple-borer,  attack 
healthy  trees  and  often  cause 
their  destruction.  One  of  the 
common  smaller  species  is  the 
red-necked  blackberry-borer. 
It  is  a  third  of  an  inch  long, 
with  black  wing-covers,  dark 
bronze  head,  and  coppery 
bronze  prothorax.  The  larva  bores  in  the  sapwood  of  the  rasp- 
berry and  blackberry,  causing  a  gall-lik^  swelling,  and  when  full 
grown  bores  into  the  pith, 
where  it  pupates.  m^ 

The  fireflies  {Lampyri- 
dae)  which  twinkle  in  the 
dusk  of  a  warm  summer 
evening  are  not  realh' 
flies,  but  beetles,  though 
their  bodies  and  wing- 
covers  are  much  softer 
in  texture  than  those  of  most  beetles 


Fic.  ::oS.    Flat-headed  apple-tree  borer. 
(Twice  natural  size) 

a,  \zT\a ;    I',  beetle  ;   c,  head  of  male  ;  </,  pupa 

(After  Chittenden,   United  States  Department 

of  Agriculture) 


"..    209.     A    firefly    beetle    (P/toihius  pyralis) 
a,  lar\-a;  /',  pupa  in  cell;  c,  adult.   (.After  Kiley) 


Fig.  210.  Soldier-beetle  (Ckattli- 
ognaihus  petmsylvanicus) 

a,  larva ;    ^,   its   head   enlarged ;   c, 
adult.    (After  Riley) 


Most  of  the  fireflies  are 
medium-sized  beetles,  about  half  an 
inch  long,  of  dull  colors,  with  the  pro- 
thorax expanded  so  as  to  cover  the 
head.  They  are  nocturnal  in  habit, 
the  phosphorescent  glow  being  pro- 
duced by  the  underside  of  the  ter- 
minal abdominal  segments.  Many  of 
the  females  are  wingless  and  are  also 
phosphorescent,  being  known  as  glow- 
worms.    The    larvae    are    predacious. 


148 


ELEMENTARY  ENTOMOLOGY 


Another  group  of  this  family,  known  as  soldier-beetles,  fly  by  day 
and  are  commonly  found  feeding  on  pollen,  which  they  carry  from 
flower  to  flower,  thus  aiding  pollination.  The  common  species  are 
yellowish  with  black  markings  and  with  a  prominent  head.  The 
larvae  are  predacious  and  are  among  the  important  enemies  of  the 
larvae  of  the  codling  moth  and  plum  curculio. 

The  Leaf-Homed  Beetles  {LanielUeornid) 

The  tribe  of  leaf-horned  beetles  includes  two  families  in  which 
the  terminal  segments  of  the  antennae  are  greatly  expanded  and 
flattened,  like  plates  or  leaves,  forming  a  club. 

The  stag-beetles  (Lucanidae).  There  are  some  fifteen  species  of 
stag-beetles  in  this  country,   which  receive  their  name  from  the 


% 

^ 

p 

\ 
J 

\ 

r 

'^ 

^ 

Fig.  211.    Stag-beetles.    (Natural  size) 
At  the  left,  Lucamis  clcfltas,  male  ;  at  the  right,  Lucmuis  damn,  male.    (After  J.  B.  Smith) 

enormous  jaws  of  some  of  the  males,  which  are  branched  so  as  to 
have  a  fancied  resemblance  to  the  antlers  of  a  stag.  They  are 
large  brown  or  black  beetles,  from  an  inch  to  an  inch  and  a  half 
long,  and  the  large  mandibles  have  given  them  the  name  of  "pinch- 
ing-bugs."  The  beetles  feed  on  sap  and  decaying  wood,  and  the 
larvae,  which  are  much  like  white  grubs,  are  found  in  decaying 
trunks  and  stumps.    A  shining  black  species,  bearing  a  short  horn 


THE  BEETLES 


149 


bent  forward  on  the  head,  is  frequently  found  beneath  the  bark 
of  stumps  and  in  rotting  wood,  and  has  been  termed  the  horned 

passalus  (Passa/z/s  cornntns). 

Scarabaeidae.  With  over  five  hun- 
dred species  in  this  country,  the  Scar- 
abaeidae form  one  of  the  largest  and 
most  important  families  of  beetles. 
They  are  thick-bodied  beetles  of  the 
May-beetle,  or  June-bug,  type,  strong 
but  clumsy,  and  many  have  the  an- 
terior tibiae  broadly  flattened  for  dig- 
ging. They  may  be  divided  into  two 
main  groups,  the  scavengers  and  the 
leaf-chafers.  The  larvae  of  all  of  the 
species  are  commonly  called  white 
grubs,  for  although  they  vary  greatly 
in  size  and  structure,  they  all  have  the 
same  general  appearance  of  the  white  grub,  with  its  large  yellow 
or  brown  head  with  strong  mandibles,  long  legs,   thick,  whitish 


Fig.   212.      Passalus    coniniiis. 
(Slightly  enlarged) 

(After  J.  B.  Smith) 


Fig    213      Scarab  beetle  {Ateuchus  vanolosics)   rolling  egg  balls  of  dung,   and 
Egyptian  sculptures  of  Sacred  Scarab 

(After  Brehm) 


I50 


ELEMENTARY  ENTOMOLOGY 


body,  curved,  wrinkled,  more  or  less  clothed  with  hairs,  and  with 
the  tip  segment  of  the  abdomen  enlarged.    Of  the  scavengers,  the 

tumble-bugs  are  well  known,  as  they 
are  often  seen  rolling  balls  of  manure 
along  the  roadside,  which  are  finally 
buried  and  in  which  the  eggs  are 
laid.  The  fat  grub  feeds  within  this 
ball  until  ready  to  pupate.  The  fa- 
mous sacred  scarabaeid  was  held  in 
high  veneration  by  the  ancient  Egyp- 
tians, who  placed  it  in  their  tombs 
and  carved  it  on  sarcophagi,  stones, 
and  gems.  With  the  first  spring 
days  one  encounters  swarms  of  little 
brown,  black-spotted  beetles  which 
fill  the  air.  They  belong  to  numer- 
ous species  of  the  genus  ApJwdiiis,  the  larvae  of  which  develop  in 
manure  and  are  often  found  in  the  dung  of  horses  and  cattle  in 
pastures.    Some  of  the  scavengers  make  burrows  in  the  soil  under 


Fig.  214.    A  dung-beetle  [Apho- 

dius  granariits    Linn.).     (Greatly 

enlarged) 

(After  Forbes) 


Fig.  215.    May-beetle  [Lachnostenia  sp.),  showing  larva  (or  white 
pupa,  and  adult.    (Natural  size) 

(After  Linville  and  Kelly) 


jrub), 


THE  BEETLES 


151 


droppings,  which  they  carry  in  for  food  for  the  larvae  which  Hve 
in  the  burrows,  while  others,  known  as  skin-beetles,  feed  on  dried 
or  decomposing  animal  matter,  frequenting  the  refuse  of  tanneries 
and  eating  the  hoofs  and  hair  of  dead  animals.  Thus  the  scaven- 
gers may  be  considered  as  somewhat  beneficial,  but  the  leaf -chafers 
include  many  of  our  worst  pests.    The  June-bugs,  or  May-beetles, 


Fig.  216.    The  rose-chafer 

a,  adult;  b,  larva;  c,  d,  mouth-parts  of  same;  c,  pupa;  /,  injured  leaves  and  blossoms  of 

grape,  with  beetles  at  work,   a,  I',  e,  much  enlarged  ;  c,  d,  more  enlarged  ;  /,  slightly  reduced. 

(After  Marlatt,  United  States  Department  of  Agriculture) 


are  among  the  best-known  representatives  of  this  group.  They 
are  stout,  brown,  or  blackish  beetles  nearly  an  inch  long,  which  fly 
in  and  buzz  around  the  lights  in  early  summer.  There  are  some 
sixty  species  belonging  to  this  genus  {Lachnostcrna),  the  larvae  of 
which  are  the  typical  white  grubs  which  attack  the  roots  of  grass, 
corn,  and  garden  crops.  These  beetles  feed  at  night  on  various 
shade  and  fruit  trees,  ragging  the  foliage  as  if  it  had  been  torn. 
The  rose-chafer  is  another  well-known  species,  which  destroys  the 


1^2 


ELEMENTARY  ENTOMOLOGY 


flowers  and  leaves  of  roses  and  grapes.  It  is  a  pale  yellowish 
beetle,  three  eighths  of  an  inch  long,  somewhat  hairy,  with  long, 
pale  red  legs.  All  of  the  leaf-chafers  have  long,  spiny  legs,  whose 
use  they  do  not  seem  to  have  mastered,  for  thev  are  ridiculously 


Fig.  217.    The  rhinoceros  beetle  (Dimisies  tityrus).    (Natural  size) 
(After  Kellogg) 

awkward  in  walking.  The  largest  beede  of  this  country  is  the  rhi- 
noceros beetle  {Dynastcs  tityrus),  which  is  two  and  one  half  inches 
long,  greenish-gray  with  black  spots,  and  is  named  from  the  large 
horn  on  the  head,  which  meets  a  median  horn  extending  from  the 

prothorax.  It  occurs  in  the  South  and 
West,  and  in  the  W'est  Indies  there  is  a 
similar  species  six  inches  long.  Their 
larvae  live  in  the  roots  of  decaying  trees. 
Another  series  of  species  are  known  as 
flower-beetles,  from  their  habit  of  feeding 
on  pollen,  which  they  carry  from  flower  to 
flower.  A  common  species  of  this  sort  is 
the  yellowish-brown  bumble  flower-beetle 
{EnpJioria  inda).  It  is  half  an  inch  long, 
quite  hairy,  and  flies  from  flower  to  flower 
with  a  loud  buzzing  like  that  of  a  bumble- 
bee. Occasionally  these  beetles  assemble 
on  ripening  peaches  or  other  soft  fruits,  or  lap  up  the  sap  from  a 
wounded  tree.  A  bright-green  species  {Alloi-hina  nitida),  two 
thirds  of  an  inch  long,  is  very  common  in  the  South,  where  it  is 
often  called  the  green  June-bug,  and  frequently  attacks  ripening 
fruits, 
often  injure  lawns 


Fig.  218.  The  bumble  flower- 
beetle  (£■///// (?;7rf  htJa).  (Twice 
natural  size) 

(After  Chittenden,  United  States 
Department  of  Agriculture) 


The  larvae  are  white  gmbs  which  live  in  grasslands  and 


THE  BEETLES 


153 


II.    BEETLES  WITH  FOUR-JOINTED  TARSI  {TETRAMERA) 

The  tarsi  of  the  famihes  of  this  section  are  apparently  composed 
of  but  four  segments,  the  fourth  being  very  small  and  closely  joined 
to  the  last,  or  fifth,  segment,  and  concealed  by 
the  third  segment,  which  is  deeply  bilobed.  This 
section  is  often  called  the  Phytophaga,  as  all  of 
the  families  attack  vegetation. 

The  leaf-beetles  (Chrysomelidae)  are  one  of  the 
largest  and  most  injurious  families,  there  being 
some  six  hundred  species  in  this  country,  a  large, 
number  of  which  injure  cultivated  crops,  while 
those  which  normally  feed  on  various  weeds  often 
change  their  food  habits  and  become  crop  pests. 
The  Colorado  potato-beetle  {Leptinotarsa  decem- 
liiicata)  is  one  of  the  best-known  species,  and  is 
fairly  typical  of  the  family,  except  that  it  is  much 
larger  than  the  average.  The  little  black,  red-and- 
yellow-spotted  asparagus-beetles  which,  with  their 
dark  grayish,  sluglike  larvae,  eat  into  young  aspar- 
agus, are  well  known  throughout  the  East,  as  are 
the  twelve-spotted  asparagus-beetles,  which  are  red  with  twelve 
black  spots. 


Fig.  219.  Tarsus 
of  phytophagous 
beetle,  showing 
indistinct  fourth 
segment 

(After  Comstock, 
from  Hunter) 


Fig.  220.  The  common  asparagus-beetle,  —  eggs,  larva,  and  adult.  ( Much  enlarged) 

(After  Britten) 


154 


ELEMENTARY  ENTOMOLOGY 


From   North  Carolina  and  Ohio  to  Maine  the  elm  leaf-beetle 
{Galeriicclla  Intcola)  is  the  worst  insect  pest  of  elm  foliage,  both 


Fig.  221.    The  Colorado  potato-beetle.    (Enlarged) 

«,  beetle ;  b,  eggs ;  <-,  young  larva ;  </,  full-grown  larva.     (After  Chittenden,  United  States 
I^epartment  of  Agriculture) 

adults  and  larvae  skeletonizing  the  leaves  and  so  defoliating  trees 
that,  where  injured  annually,  many  are  killed.  The  beetles  are 
one  fourth  of  an  inch  long,  yellowish-brown,  with  black  stripes  at 


THE  BEETLES 


155 


the  outer  margin  of  the  wings,  and  the  full-grown  larvae  are  half 
an  inch  long,  orange-yellow,  with  numerous  black  tubercles.    The 


Fig.  222.    The  elm  leaf-beetle 

/,  cluster  of  eggs;  i a,  single  egg;  2,  newly  hatched  larva;  j,  full-grown  larva;   4^  pupa; 

J,  overwintered  beetle  ;  6,  newly  transformed  beetle  ;  7,  leaf  showing  work  of  grubs  and  a  few 

holes  eaten  by  beetles  ;  5,  leaf  nearly  skeletonized  by  larvae  ;  g,  leaf  showing  holes  eaten  by 

beetles.    (All  enlarged  except  7,  5,  q,  which  are  slightly  reduced.)    (After  Felt) 


156 


ELEMENTARY  ENTOMOLOGY 


Fig.  223.  Striped 
cucumber-beetle 


Striped  cucumber-beetle  {Diahrotica  vittatd)  is  about 
the  same  size,  bright  yellow  with  black  stripes,  and 
is  one  of  the  worst  pests  of  young  cucumber  and 
melon  vines.  The  larvae  are  long,  slender  whitish 
grubs  which  feed  on  the  roots.  The  twelve-spotted 
Diabrotica  is  green  with  twelve  black  spots,  with 
similar  food  habits  in  the  adult  stage,  but  in  the 
South  the  larvae  do  serious  injury  to  the  roots  of 
corn,  while  the  larva  of  another  pale  green  species, 


Fig.  224.  A,  potato  flea-beetle  ;   /?,  egg-plant  flea-beetle. 
(Both  greatly  enlarged) 

(After  Chittenden,  United  States  Department  of  Agriculture) 


known  as  the  west- 
ern corn  rootworm, 
is  one  of  the  worst 
pests  of  corn  in 
the  northern  Miss- 
issippi Valley.  A 
large  group  of  small 
species,  with  strong 
hind  legs  which  en- 
able them  to  give 
remarkable  jumps, 
are  known  as  flea- 
beetles.  The  potato 
flea-beetle  {Epitrix  fnscitla)  and  nearly  related  species  are  com- 
monly abundant  on  young  potato  and  tomato  plants,  and  on  egg- 
plants, the  leaves  of  which  are 
.  .  __  riddled  as  if  they  had    been    hit 

-'j^-''C  a'"^^^!^"'^^ f        ^^^^'^  ^^^  ^^''^  shot.    The  larvae  are 

small,  slender  white  grubs,  which 
feed  on  the  roots  of  various  weeds 
of  the  same  botanical  family,  and 
are  rarely  seen.  All  the  garden 
1      l"^^ri_  WiJLI^/  crops,  as  well  as  tobacco  and  corn, 

1      ^i^m  \^^/  7.        are  attacked  by  one  or  more  spe- 

cies of  these  flea-beetles.  The  lar- 
vae of  a  few  species  of  this  family 
are  leaf  miners,  the  leaves  of  the 
locust  being  commonly  affected  by 
large,  brown,  blisterlike  mines  due 


Fig.  2: 


5.    Striped  turnip  flea-beetle 
(Greatly  enlarged) 


«,  lar\'a :  b,  adult.    (From  Riley,  United 
States  Department  of  Agriculture) 


THE  BEETLES 


157 


to  the  larvae  of  the  locust-beetle  (Odontota  dorsalis).   On  morning- 
glory  and  sweet-potato  vines  are  found  some  striking  little  beetles, 


Fig.  226.    The  leaf-mining  locust-beetle  {Odontota  dorsalis). 
(Five  times  natural  size) 

a,  beetle  ;  /',  larva ;  r,  pupa,    (.\fter  Chittenden,  United  States  Department  of  Agriculture) 

called  tortoise-beetles,   from   their  tortoiselike   shape,    several    of 
which  are  a  brilliant  gold  or  silver  color.    The  larvae  feed  on  these 


Fig.  227.    The  golden  tortoise-beetle  [Coptocycla  bicolor  Fab.)  ; 
egg  at  right.    (Enlarged) 

rt,  b,  larvas  •,  c,  pupa  ;  d,  beetle.    (After  Riley) 

plants,  and  are  curious  little  creatures,  canying  a  mass  of  excre- 
ment over  the  back,  which  has  given  them  the  name  "peddlers." 


158 


ELEMENTARY  ENTOMOLOGY 


The  pea-weevil  family  (Bruchidae)  includes  the  small  weevils 
which  commonly  infest  peas,  beans,  and  Other  seeds.  They  are  of 
much  the  same  general  shape  as  some  of  the  leaf-beetles,  but  the 

head  is  prolonged  into 
a  blunt  snout,  and  the 
wing-covers  are  square 
at  the  tip,  leaving  the 
tip  of  the  abdomen  ex- 
posed. They  are  from 
one  eighth  to  one  fourth 
of  an  inch  long,  brown- 
ish or  ashen  gray  in 
color,  with  whitish  scales 
or  hairs  on  the  wing- 
covers,  forming  various 
markings.  Both  beetles  and  larvas  feed  on  seeds  of  leguminous 
plants,  of  which  they  are  the  most  serious  insect  pests. 

The  long-horned  beetles  (Cerambycidae)  are  easily  recognized  by 
the  long  antennae,  which  are  rarely  shorter  than  the  body  and 
often  are  twice  as  long.    They  are  large,  stout,  cylindrical-bodied 


Fig.  228.    The  pea-weevil.    (Enlarged) 

a,  adult  beetle  ;    /',  lan-a  ;    c,  pupa.    (After  Chittenden, 
United  States  Department  of  Agriculture) 


a  c 

Fig.  229.    The  common  bean-weevil.    (All  enlarged) 
a,  beetle  ;  b,  larva  ;  r,  pupa.    (After  Chittenden,  United  States  Department  of  Agriculture) 

beetles,  usually  strikingly  colored  and  patterned,  attracting  imme- 
diate attention.  The  larvae  are  cylindrical  white  grubs  which  bore 
in  the  heartwood  of  trees  and  are  termed  round-headed  borers,  in 
contrast  to  the  flattened  forms  of  the  Bnprestidae.    The  family  is  a 


Fig.  230.    The  round-headed  apple-tree  borer,  —  larvee,  adults,  and  exit  hole. 

(Natural  size) 

(After  Rumsey  and  Brooks) 


Fig.  231.    Work  of  the  round-headed  apple-tree  borer.    (Natural  size) 

rt,  puncture  in  which  egg  is  laid  ;  b^  same  in  section  ;  r,  hole  from  which  beetle  has  emerged  ; 
/,  same  in  section  ;  g,  pupa  in  its  cell.    (After  Riley) 

159 


i6o 


ELEMENTARY  ENTOMOLOGY 


large  one  and  includes  many  serious  pests,  such  as  the  round- 
headed  apple-tree  borer  and  others  with  similar  habits.  Three  com- 
mon blackish  species,  brilliantly  striped 
with  yellow  (Fig.  234),  are  known  as 
locust-borer,  hickory-borer,  and  sugar- 
maple-borer,  after  their  respective  food 
plants,  which  are  frequently  killed  from 
the  work  of  their  larvae.  Among  our 
largest  beetles  are  the  prionids,  the  larvae 
of  which  infest  the  roots  of  various  fruit 
and  shade  trees  and  herbaceous  plants. 
The  broad-necked  prionus  is  from  one 
to  two  inches  long,  pitchy  black,  with  the 
thin  margin  of  the  prothorax  toothed,  as 
shown  in 
Fie 


232. 
The  oak- 


FiG.  232.  The  giant  root-borer 
(Prioiiiis  laticollis) 

(After  Riley) 

pruner  is 
a  slender,  brown  species,  about  three 
fourths  of  an  inch  long,  which  lays 


Fig.  234.  Thehickorv-borer  {Cylleiu 
pictiis  Dru.).    {Enlarged) 

(After  Webster) 


Fig.  233.    The  oak-pruner  {Elaphi- 
dion  pai-alUliim) 

a,  larva  ;  /',  pupa  in  its  burrow  ;  c,  beetle  ; 
k,  k,  cut  ends  of  twig.    (After  Riley) 

its  eggs  in  the  twigs  of  oak,  maple, 
and  various  fruit  trees.  The  larvae 
hollotv  out  the  interior  of  the  twigs 
which  are  broken  off  by  the  winds, 
and  in  these  they  pupate.  One  of 
our  largest  species  is  the  common 
sawyer,  a  large  gray  beetle  one 
and  one  fourth  inches  long,  with 
very  long  antennae,  whose  larvae 
bore  into  the  heart  of  felled  pine 
and  other  softwood  trees,  making 
large  holes  half  an  inch  in  diameter. 
The  raspberry  cane-borer  {Obcrea 


THE  BEETLES 


l6l 


hiniacitlata)  is  a  black  beetle  half  an  inch  long,  with  yellow  pro- 
thorax  bearing  two  black  spots.  Its  larva  mines  raspberry'  and 
blackberry  canes.  The  red  milkweed-beetles  {Tetraopes  tctra- 
ophthalnius)  are  always  common  on  the  flowers  of  the  milkweed, 
and  the  larva  bore  in  the  roots  and  stems. 

III.   BEETLES   WITH   THREE-JOINTED  TARSI    [TRIMERA) 

The  ladybird-beetles  (Cocdnellidae)  form  the  only  family  of  the 
section  Trwiera,  in  which  the  tarsi  have  but  three  segments,  and 


Fig.  235.    The  convergent  ladybird-beetle  [Hippodamia  convergens) 
a,  adult ;  /',  pupa  ;  <-,  larva,    (.\fter  Chittenden) 

the  head  is  usually  concealed  beneath  the  prothorax.  Their  small 
size  (few  being  over  one  fourth  of  an  inch  long),  their  broad,  oval,  or 
hemispherical  shape, 
and  their  characteris- 
tic markings,  consist- 
ing of  "polka-dot" 
black  spots  on  a  yellow 
or  red  background, 
or  red  or  yellow  spots 
on  black,  make  them 
readily  recognizable, 
though  now  and  then 
certain  of  the  leaf- 
beetles,  which  have  a 

1  ,  ,  Fk;.  2^6.    The  spotted  ladybird-beetle  (Mes^/lia 

general  resemblance,  ^  ^  ,■   ,  " 

are  mistaken  for  them.        ,        ,  au  ,^(,    nu..    a     ttv^c.  . 

a,  larva  ;  d,  pupa  :  c,  adult.   (.After  Chittenden,  United  States 
Nearly      all      of      this  Department  of  .\griculture) 


l62 


ELEMENTARY  ENTOMOLOGY 


Fig.  2 


J/.    The  nine-spotted  ladybird-beetle  {Cccci- 
nella  novetnnotata),  —  adult  and  larva 

(After  Chittenden) 


family  feed  on  plant-lice,  scales,  and  other  soft-bodied  insects, 
both  as  adults  and  as  lan^ae,  and  may  be  found  wherever  their 
prey  becomes  abundant.    In  general  the  common  yellow  or  red, 

black-spotted     species 

feed      on      plant-lice, 

while  the  smaller  black 

species,   marked  with 

red  or  yellowish  spots, 

feed    on    scales.     So 

I  igiM.^^^^^  4  iULM^         common  are  the  ladv- 

^^^^^>     /i  A^>  birds  among  colonies 

^    ^--et*-^    C  ^^f  of  plant-lice  that  they 

are  frequently  mis- 
taken as  the  parents 
of  the  aphides,  and 
the  misguided  grower 
carefully  picks  them  off  and  destroys  them,  thinking  he  is  elimi- 
nating the  cause  of  the  aphid  infestation,  whereas  he  is  really 
destroying  nature's  most  efficient  agents  for  its  alleviation.  The 
eggs  are  laid  in  little  yellow  masses  on  the  leaves  or  bark  where- 
ever  food  is  abundant.  The  lan-^  are  commonly  about  one  fourth 
of  an  inch  long,  strongly  tapering  at  either 
end,'  with  long  legs,  and  often  marked 
with  spiny  processes.  They  run  here  and 
there  in  search  of  food,  feed  voracioush- 
on  any  unlucky  plant-lice  or  insects'  eggs 
which  fall  in  their  path,  and,  when  full 
grown,  attach  themselves  to  bark,  leaves, 
or  fences  by  the  tip  of  the  abdomen  and 
there  pupate,  the  cast  lar\^al  skin  often 
remaining  over  the  pupa.  The  beetles 
hibernate  over  winter.  The  nine-spotted 
ladybird  {Coccinella  g-notata)  is  one  of  the  larger  common  }"ellow 
species,  with  nine  black  spots,  and  the  little  two-spotted  ladybird 
{Adalia  bipiinctata)  is  smaller,  slightly  broader,  and  frequently 
associated  with  the  former  species.  The  twice-stabbed  ladybird 
{Chiloconis  biviilnerns)  is  black  with  a  red  spot  on  each  wing-co\'er. 
Its  spiny  larv'a  is  black,   and,  with  the  adult,  feeds  upon  scale 


Fig.  238.   The  twire-stabbed 

ladybird-beetle     {Chi/oconts 

biviilnerits  Muls.)  and  laiA'a. 

(Enlarged) 

(.A.fter  Riley) 


THE  BEETLES 


163 


insects,  often  checking  their  increase  notice- 
ably. Recently  a  very  similar  species,  the 
Asiatic  ladybird,  was  imported  from  China  to 
prey  upon  the  San  Jose  scale,  but  has  not  be- 
come established  in  this  country.  Several  very 
small,  black  species  of  the  genus  Microweisea, 
with  their  little  black  larvae,  are  also  among 
the  most  effective  enemies  of  scale  insects. 
One  of  the  most  remarkable  cases  of  the 
utilization  of  a  beneficial  insect  was  the  intro- 
duction into  California  of  the  Australian  lady- 
bird {Vedalia  cardinalis),  which  in  a  few  years 
was  able  to  almost  entirely  subdue  the  cottony 
cushion-scale,  which  was  destroying  the  orange 
trees.  Unfortunately,  there  are  some  sinners 
among  the  ladybirds,  for  there  are  one  or  two 
large,  hemispherical,  black-spotted,  yellow  spe- 
cies of  the  genus  Epilachna,  which  defoliate 
Fig.  239.  Pup^  of  the  cucumbers,  melons,  and  beans. 

twice-stabbed  ladybird- 
beetle,    in    cast  larval 
skins 


IV.  BEETLES  WITH  DIF- 
FERENT-JOINTED TARSI 
{HETEROMERA) 

The  section  Hctcroin- 
era  is  distinguished  by 
having  the  front  and  mid- 
dle feet  with  five  tarsal 
segments,  while  the  hind 
feet  have  but  four ;  hence 
the  name  "different- 
jointed."  A  number  of 
small,  obscure  families 
are  included  in  this  sec- 
tion, only  two  being  of 
sufficient  importance  to 
warrant  consideration. 


Fig.    240.     Australian    ladybird-beetle    (JVovius 

cardinalis),    the    enemy    of    the    white    scale. 

(Natural  size) 

a,  ladybird  lan'ae  feeding  on  adult  female  and  egg  sac ; 

/',  pupa ;    c,  adult  ladybird  ;    d,  orange  twig,  showing 

scales  and  ladybirds.    (After  Marlatt,  United  States 

Department  of  Agriculture) 


Fig.  241.    Mkroweisea  misella,  a  small  black  ladybird-beetle  which 
feeds  on  scales.    (All  greatly  enlarged) 

(?,  beetle ;  /',  larva ;  c,  pupa ;  d,  blossom  end  of  pear,  shovvino;  San  Jose  scales  upon  which 

the  beetles  and  their  larvae  are  feeding,  and  pupae  in  the  calyx.   (After  Howard  and  Marlatt, 

United  States  Department  of  Agriculture) 


Fig.  242.    The  squash  ladybird-beetle 

(7,  larva  ;  b,  pupa ;  f,  adult  beetle  (three  times  natural  size) ;  </,  egg  (four  times  natural  size) ; 
e,  surface  of  egg   (highly  magnified).    (After  Chittenden,  United   States  Department  of 

Agriculture) 
164 


THE  BEETLES 


i6^ 


The  darkling  beetles  (Tenehrionidae)  live  mostly  under  bark  and 
stones,  are  dull  black,  and  have  much  the  same  gejieral  appearance 
as  the  ground  beetles.    They  are  much  more  abundant  on  the 


QQ::cca^oc::c:c>._ 


Fig.  243.    The  meal-worm  (  Tenehrio  molitor) 

(7.  lana  :  /■,  pupa;  c,  female  beetle  ;  </,  egg  with  surrounding  case  ;  f,  antenna.  (.\n  excepts 
about  twice  natural  size  ;  <-,  greatly  enlarged.)    (.After  Chittenden,  United  -States  Department 

of  Agriculture) 

Pacific  coast  and  in  the  Rockies,  relatively  few  forms  being  found 
in  the  East.  A  common  species  of  the  typical  genus  is  the  meal- 
worm beetle  {Tenebrio  molitor)  which  infests  grain-rooms,  stores, 


/ 

Fig.  244.    The  striped  blister-beetle 

(7,  female  beetle :  h,  eggs ;  c,  triungulin  lar\-a :  d,  second  or  carabid  stage  of  larva ;  e,  same 

as/  doubled  up  as  in  pod  ;  /,  scarabaeoid  stage  ;  ^c-  coarctate  lar\'a.   (All  except  e  enlarged.) 

(After  Riley  and  Chittenden,  United  States  Department  of  Agriculture) 


1 66 


ELEMENTARY  ENTOMOLOGY 


Fig.  245.    The  black  blister 
beetle.    (Enlarged) 


pantries,  and  wherever  meal  is  stored.  The  larvae  are  elongate, 
brown,  and  horny,  veiy  much  resembling  wire-worms,  and  are 
kept  by  bird  fanciers  for  feeding  song 
birds  in  winter.  The  beetle  is  from  one 
half  to  three  fourths  of  an  inch  long,  dark 
brown,  with  square  prothorax  and  ridged 
wing-covers. 

The  blister-beetles  (Meloidae)  are  so 
called  because  their  juices  cause  a  blis- 
tering of  the  human  skin,  and  when 
dried  and  powdered  they  were  formerly 
much  used  by  phy- 
sicians for  blister- 
ing. They  are  soft- 
bodied  beetles  with 

(After  Chittenden,  United  States     ^^g  head  prominent 
Department  of  Agriculture)  ^ 

and  attached  to  the 

thorax  by  a  very  distinct  neck.    The  elytra 

are    flexible    and    rounded    posteriorly,    so 

that    usually    they    do    not    cover    the    tip 

of  the  abdomen, 
while  in  some  forms 
the  wing-covers  are 
quite  short  and  the 
wings  are  lacking. 
Our  common  spe- 
cies are  about  half 

an  inch  long,  dull  gray  or  blackish,  often 
marked  with  yellow  stripes,  while  others 
are  of  a  brilliant  metallic  bronze,  green, 
or  blue.  The  adults  often  appear  in  im- 
mense swarms  and  ruin  garden  crops. 
The  striped  blister-beetle  {Epicaiita  vit- 
tata)  was  a  common  pest  of  potatoes 
before  the  advent  of  the  Colorado  beetle, 
and  is  known  as  the  "old-fashioned  potato- 
bug."  The  larvae  have  a  very  complicated 
metamorphosis,  owing  to  their  peculiar 


Fu;.  246.     The   ash-gray 
blister-beetle.   (Twice  nat- 
ural size) 

(After    Chittenden,    United 
States  Department  of  Agri- 
culture) 


Fig.   247.     The   white-pine 
vi&t\\\(Pissodes  st7vbi).    (En- 
larged and  natural  size) 

(After  Hopkins,  United  States 
Department  of  Agriculture) 


'JHE   BEETLES 


167 


habits.  Some  of  them  are  parasitic  in  the  nests  of  bees,  while  tlie 
more  common  forms  hve  on  the  eggs  of  grasshoppers,  which  they 
devour  in  large  numbers,  and  are  quite  bene- 
ficial in  spite  of  the  bad  habits  which  they 
later  acquire  as  adults. 

The  Snout-Beetles  {Rhynchophora) 

In  this  suborder  the  head  is  prolonged 
into  a  long  snout,  giving  the  names  "snout- 
beetles  "  "bill-bugs,"  "weevils,"  and  "cur- 
culios "  to  many  of  the  common  forms. 
The  body  is 


Fig.   248.     The   straw- 
berry weevil.    (Greatly 
enlarged) 

(After  Riley) 


strongly  com- 
pact, usually 
well  rounded 
above,  and  is 
more  or  less  covered  with  scales. 
The  antennae  arise  from  either 
side  of  the  snout,  are  bent  for- 
ward, or  "elbowed,"  and  end  in 
a  club.  The  larvae  are  soft,  foot- 
less, wrinkled,  whitish  grubs,  with 
brown  head,  often  thinly  covered 
with  short,  bristly  hair,  and  live 
mostly  in  fruits,  nuts,  or  seeds, 
or  under  bark,  though  a  few  live 
on  vegetation  externally.  All  of 
the  families  attack  plants  and  are 
therefore  more  or  less  injurious. 


Fig.  250. 


Head  and  mouth-parts  of  the 
boll  weevil  larva 


Fig.  249.    The  cotton-boll  weevil. 
(Enlarged) 

some  of  our  most  troublesome 
pests  being  found  in  this  series. 
Though  there  are  common  ex- 
amples of  several  other  families, 
only  three  families  are  suffi- 
ciently numerous  to  warrant 
mention. 

The  curculios  (Curculionidae) 
are  the  most  typical  as  well  as  the 
largest  family  of  the  suborder. 


1 68 


ELEMENTARY  ENTOxMOLOGY 


with  over  six  hundred  species.    With  her  long  snout  the  female 
drills  into  fruits  and  stems  and  drops  an  egg  in  the  bottom  of  the 

excavation.  Here  the  larva 
feeds  within  the  food  plant, 
well  protected  against  attack. 
In  the  northeastern  states  a 
brownish  beetle,  about  one 
fourth  of  an  inch  long,  with  a 
white  spot  on  each  wing-cover, 
known  as  the  white-pine  weevil 
{Pissodcs  strobi),  lays  its  eggs 
in  the  axis  terminal  of  pines, 
which  the  larva  tunnels  out  and 
kills,  completely  spoiling  the 
The  plum  curculio 


Fig.  251.    Larva  of  the  cotton-boll  weevil 
in  opened  square.    (Natural  size) 


shape  of  the  tree, 
is  the  well-known  little  Turk  which 
makes  the  crescent-shaped  punctures 
on  plums,  peaches,  cherries,  and  apples, 
and  whose  grubs  feed  within.  A 
small  blackish  weevil,  the  strawberry 
weevil  {AntJiononius  signatus),  lays 
its  eggs  in  the 


Fig.  252.    The  chestnut  weevil 

(Bala?iimis  proboscideus   Fab.). 

(Natural  size) 


Fig.  253.    A  corn  bill-bug 

{SpAeitopkonis  ochreus). 

(Twice  natural  size) 

(After  Webster) 


Strawberry  buds, 
which  it  then 
cuts  off,  and  the  larvae  feed  on  the  develop- 
ing flowers,  often  causing  serious  loss.  The 
cotton-boll  weevil  {Anthonovuis  graudis)  is 
probably  the  most  import^mt  species  from 
an  economic  standpoint,  causing  a  loss  of 
over  twenty-five  million  dollars  annually. 
The  most  striking  of  all  the  weevils  are 
the  acorn  and  chestnut  weevils,  with  snouts 
much  longer  than  the  body,  enabling  them 
to  drill  through  the  chestnut  bur  and  de- 
posit the  egg  within  the  nut,  in  which  the 
larva  develops.  Almost  all  of  our  common 
nuts  are  attacked  by  some  species  of  these 
weevils,  which  often  are  a  serious  nuisance. 


THE  BEETLES 


169 


The  bill-bugs  {Calandridae)  are  from  one  fourth  to  one  half  of  an 
inch  long,  black,  brown,  or  dark  gray,  with  hard  elytra,  ridged  and 


Fig.  254.    The  gxciw^ry  weexW  (Cala/iJfa  gni/iarhi).    (Enlarged) 


a,  beetle  ;  /',  lan-a  ; 


pupa;  (/.  the  adult  rice  weevil  {Calandra  o>y~<^)-    (After  Chittenden, 
United  States  Department  of  Agriculture) 


sculptured.    They  attack  corn,  timothy,  and  other  grasses,  particu- 
larly the  coarse  swamp  grasses  and  sedges.    The  fat  white  larvse 


«^  led 

Fig.  255.    The  fruit-tree  bark-beetle  {Scolyttis  ntgulosits) 

a,  adult ;  li,  same  in  profile  ;  c,  pupa ;  </,  larva  (about  ten  times  natural  size).    (After 
Chittenden,  United  States  Department  of  Agriculture) 

live  in  the  crowns  and  stems  of  the  plants.    More  important  are 
the  small  granary  and  rice  weevils  {Calandra  gran  aria  and  oryza), 


I/O 


ELEMENTARY  ENTOMOLOGY 


small,  slender,  brown  weevils,  one  eighth  of  an  inch  long,  which 
are  the  most  abundant  pests  of  granaries. 

The  engraver-beetles  {Scolytidae),  or  bark-beetles,  live  on  the 
inner  bark  and  sapwood  of  forest  and  fruit  trees,  the  larvae  of 
each    brood    tunneling   out  their  little  burrows   in  characteristic 

patterns,  giving  them  the  name 
of  "engravers."  They  are  small 
brown  or  blackish  beetles,  often 
microscopic,  rarely  over  one  eighth 
-  and  never  over  one  fourth  of  an 
inch  long,  and  with  the  head  very 
slightly  produced,  so  that  they  are 
not  readily  recognized  as  snout- 
beetles.  They  have  stout,  cylin- 
drical bodies,  obliquely  or  squarely 
truncate  at  the  tip.  The  larvae  are 
little  white  grubs,  with  brown 
heads  and  strong  jaws,  which 
riddle  the  inner  bark  of  the  food 
plant  and  pupate  in  the  burrows. 
When  the  adults  emerge,  they  make 
numerous  small  holes  through  the 
bark,  which  habit  has  given  them 
the  name  of  "  shot-hole  borers." 
This  family  includes  the  most  de- 
structive of  all  our  forest  insects, 
the  losses  due  to  them  being  es- 
timated at  over  one  hundred  million 
dollars  per  annum.  Almost  every 
tree  has  species  which  commonly 
attack  it  in  different  sections  of 
the  country,  some  infesting  only 
sick  or  dead  timber,  while  others 
attack  the  healthy  trees  and  sweep  them  off  over  large  areas,  the 
trees  dying  and  giving  rise  to  forest  fires.  The  fruit-tree  bark- 
beetle  {ScolytTis  riigulosus)  is  a  well-known  example,  infesting  our 
common  fruit  trees. 


Fig.  256.  Typical  worK  of  a  scolytid, 
the  fruit-tree  bark-beetle,  showing 
the  main  galleries,  the  side  or  larval 
galleries,  and  the  pupal  cells.  (Slightly 
enlarged) 

(After  Ratzeburg) 


THE  BEETLES 


171 


Synopsis  of  Families  of  Beetles 


Suborder  Typical  beetles  (Coleopiera  geiiuina) 
Section  i.  With  five-jointed  tarsi  {Pentamera) 
Tribe  i.  Carnivorous  beetles  (A dep/iaga) 

Tiger-beetles  (Cici?idelidae) 

Ground-beetles  {Carabidae) 

Predacious  diving-beetles  {Dy/iscidae) 

Whirligig-beetles  ( Gyrinidae) 
Tribe  2.  The  club-horned  beetles  (Cla%iicornid) 

Water-scavenger  beetles  {Hydrophilidae) 

Carrion-beetles  {Silphidae) 

Rove-beetles  (Sfaphyll/iidae) 

Cucuj id-beetles  ( Citcujidae) 

Dermestid-beetles  {Dennestidae) 
Tribe  3.  The  saw-horned  beetles  [Serricornid) 

Click-beetles  (Elateridae) 

Metallic  wood-borers  [Bupresildae) 

Fireflies  {Lampyridae) 
Tribe  4.  The  leaf-horned  beetles  {Lainellicontia) 

Stag-beetles  {Lucanidae) 

Scarabaeid  beetles  [Scambcieldae) 

Section  2.  With  four-jointed  tarsi  {Tetramerd) 
Leaf-beetles  ( Ch/yso/nelidae) 
Pea-weevils  {Bnichidae) 
Long-horned  beetles  (Cerambycidae) 

Section  3.  With  three-jointed  tarsi  (Triinera) 
Ladybird-beetles  ( Coccinellidae) 

Section  4.  With  different-jointed  tarsi  (Heicrovierd) 
Darkling-beedes  ( Tenebrionidae) 
Blister-beetles  [Meloidae) 

Suborder  Snout-beetles  {RliyncIiopJiord) 

The  curculios  [Cmrulio/iidae) 

The  bill-bugs  (Calmidridae) 

The  engraver-beetles,  or  bark-beetles  (Scolytidae) 


CHAPTER   XIII 


THE  BUTTERFLIES   AND  MOTHS    (LEPIDOPTERA) 

Characteristics.  Insects  with  four  wings,  which  are  membranous  and  cov- 
ered with  overlapping  scales  ;  mouth-parts,  suctorial ;  metamorphosis,  complete. 

If  the  wing  of  a  butterfly  or  a  moth  is  rubbed,  the  color  is  quickly 
removed  as  a  sort  of  powder,  leaving  the  transparent  membranous 
wing.  If  this  powder  is  examined  with  a  microscope,  it  will  be  seen 
to  be  composed  of  small,  finely  ridged  scales,  which  are  arranged 

on  the  wings  in  overlapping 
rows  and  give  it  the  charac- 
teristic color  pattern.  Thus 
we  get  the  name  of  the  order, 
from  lepis  (a  scale)  and  pteron  (a 
wing).  These  scales  strengthen 
the  wings  and  are  also  found 
on  the  body  and  on  other  ap- 
pendages. The  mouth-parts  of 
the  adults  consist  of  a  long, 
tubelike  proboscis,  which  is 
coiled  under  the  head  when 
not  in  use,  looking,  in  some  of 
the  larger  moths,  much  like  a 
watch  spring.  It  is  composed 
of  the  two  maxillae,  the  inner 
faces  of  which  are  grooved  and 
locked  together  so  as  to  form 
a  tube,  through  which  the  nectar  of  flowers  is  sucked.  The  man- 
dibles are  entirely  wanting.  The  two  brushlike  organs  on  either 
side  of  the  proboscis  are  the  labial  palpi,  the  balance  of  the  labium 
being  poorly  developed. 

The  larvae  of  butterflies  and  moths  are  known  as  caterpillars. 
They  are  quite  variable  in  shape,  but  our  common  forms  are  readily 
recognizable  as  belonging  to  this  order.  They  are  usually  cylindrical, 

172 


Fig.  257.    Portion  of  wing  of  monarch 
butterfly,  with  some   scales   removed  to 
show  insertion-pits  and  their  regular  ar- 
rangement.     (Greatly  magnified) 

(After  Kellogg) 


THE   BUTTERFLIES  AND  MOTHS 


173 


\ 


\ 


X'^Sj" 


<^ 


-^ 


Fig.  258. 


with  a  well-developed  head  bearing  biting  mouth-parts  and  small 
ocelli  on  either  side.  The  thorax  bears  three  pairs  of  jointed  legs, 
which  terminate  in  a  single  claw,  and  the  back  of  the  prothorax 

forms  a  hard  shield, 
thepronotum.  Theab- 
dominal  segments  are 
very  similar  and  bear 
from  one  to  five  pairs 
of  short,  fleshy,  unseg- 
mented  false  legs,  or 
prolegs,  which  termi- 
nate in  a  circle  of  small 
hooks,  one  pair  of 
which  is  always  borne 
by  the  anal  segment. 
The  caterpilMrs  of 
many  moths  pupate  in 
little  cells,  which  they 
hollow  out  in  the 
ground,  but  most  of 
them  spin  silken  co- 
coons, within  which  they  pupate.  Some  are  thin,  flimsy  affairs,  while 
others,  like  those  of  the  silkworm,  contain  a  large  amount  of  silk 
and  are  very  firmly  built,  forming 
a  warm  home  for  the  hibernating 
pupae.  Butterfly  larvae  spin  no  co- 
coons, and  the  pupae,  or  chrysalids, 
hang  pendent  from  the  food  plant 
or  some  near-by  object,  to  which  they 
are  lashed  by  a  strand  of  silk  around 
the  body. 

The  order  is  one  of  the  largest, 
including  over  sixty-six  hundred  spe- 
cies in  this  country,  and  contains 
many  of  our  most  serious  pests,  while 

very  few  of  its  members  are  beneficial.  The  families  are  largely 
distinguished  by  the  wing  venation,  which  is  difficult  to  see,  so  that 
it  is  exceedingly  hard  to  arrange  them  in  any  natural  and  easily 


Luna  moth,  showing  pectinate,  or  feath- 
ered, form  of  moth  antennae 

(After  S.  J.  Hunter) 


Fig.  259.   A  skipper  (^Fjidanuis  ba- 
i/iy!liis],  showing  recurved  tips  of 
antennas 

(After  S.  J.  fiunter) 


174 


ELEMENTARY  ENTOMOLOGY 


recognizable  groups.  The  caterpillars  of  the  different  families  may 
be  recognized,  to  a  certain  extent,  by  their  habits  and  general 
appearance.  The  butterflies  and  moths  form  two  main  divisions 
of  the  order,  which  are  readily  distinguished. 

Butterflies 

The  butterflies  are  day  fliers,  and  when  at  rest  the  wings  are  held 
in  a  vertical  position  over  the  back.  The  antennae  are  threadlike 
and  are  distinctly  enlarged  at  the  tip. 

The  butterflies  are  much  less  numerous  than  the  moths,  both 
in   families    and   in    species,   and   include   relatively   few   species 

of  any  considerable 
economic  importance. 
Two  main  groups  of 
butterflies  are  recog- 
nized, —  the  skippers 
(Hesperina)  and  the 
true  butterflies  {Pa- 
pilionina). 

SKIPPERS 

The   skippers  are 

Fig.  260.    Hop-merchant  butterfly,  showing  form  of  \\   A    ^r  fKoV 

ki  1    1     ,  r  1   ^^    n-  SO  caiieQ  irom  tneir 

nobbed  antennas  of  butterflies 

peculiar  habit  of  dart- 
ing suddenly  from 
place  to  place.  The  wings  are  held  vertically  over  the  back  when 
at  rest,  though  often  the  hind-wings  are  held  horizontally.  The 
antennae  are  enlarged  at  the  tip,  which  usually  forms  a  more  or 
less  recurved  hook.  They  have  stout  bodies,  which  resemble 
moths  more  than  butterflies.  Some  are  blackish  or  dark,  somber 
brown,  often  flecked  with  grayish  or  white,  while  others  are  tawny 
yellow  with  a  blackish  discal  patch.  The  latter  usually  have  the 
fore-wings  much  more  pointed,  and  have  thick  bodies.  The  larvae 
of  our  common  forms  have  a  characteristic  appearance  (Fig,  261), 
with  large  heads  and  strongly  constricted  necks.  They  feed  on 
foliage,  usually  concealing  themselves  within  a  folded  leaf,  which 
is  tied  together  with  silk  and  within  which  they  spin  a  loose  cocoon 


(Photograph  by  Fiske) 


THE   BUTTERFLIES  AND  MOTHS 


175 


of  silk  before  pupating.    Very  few  of  this  group  are  of  any  economic 
importance,  though  one  larva  occasionally  attacks  the  calla  lily, 


Fig.  261.  The  tityrus  skipper  {^Epargyreus  titvnts),  —  adult,  larva,  and  leaf-cocoon. 

(Natural  size) 
(After  Linville  and  Kelly) 

and  another  sometimes  injures  corn  in  the  Gulf  States,  perforating 
the  leaves  with  numerous  holes  before  they  unfold.  The  skippers 
may  be  considered  as  intermediate  be- 
tween the  moths  and  the  true  butterflies. 

TRUE  BUTTERFLIES 

The  true  butterflies  include  four  well- 
defined  families. 

The  swallowtails  (Papilionidae)  include 
our  common  black-and-yellow  species, 
which  have  the  hind-wings  prolonged 
into  characteristic  tails.  The  only  species 
of  any  economic  importance  is  the  celery, 
or  parsley,  cateipillar  {Papilio  polyxenes) 
known  swallowtail,  jet-black  with  the  outer  edge  of  the  wings 
marked  with  two  rows  of  yellow  spots,  and  a  peculiar  eyespot  on 


Fig.  262.  The  manataaqua 
skipper  (Pamphila  mana- 
taaqtia),  male.    (Natural  size) 

(After  Fiske) 

The  adult  is  our  best- 


Fig.  263.    The  black  swallowtail  butterfly  [Papilio  folyxenes).    (Slightly  reduced) 

a,  egg;   /',  caterpillar;   c,  front  view  of  head  with  osmateria  protruded;   </,  chrysalis;   <?,/, 
adult.    (After  Webster) 

176 


THE  BUTTERFLIES  AND  MOTHS 


177 


the  inner  margin  of  each  hind-wing.    Between  the  rows  of  yellow 
spots  on  the  hind-wings  are  bluish  scales,  which  are  particularly 


Fig.  264.    The  blue  swallowtail  butterfly  (Laeiiias  p/ii/enor).    (Reduced  one  fifth) 
(Photograph  by  Fiske) 

prominent  in  the  females.  The  caterpillar  is  green,  banded  with 
black  and  spotted  with  yellow,  and  feeds  on  celery,  parsley, 
parsnips,  and  nearly  related  plants.    Like  other  caterpillars  of  this 


Fig.  265.   Caterpillar 
of  the  troilus  butter- 
fly {Pupil  10  t7viins) 

(Photograph  by  \\'eed) 


Fig.    266.      The    tiger    swallowtail    butterfly 
{Papilio  glaiiciis  tuniiis).    (Reduced) 

(Photograph  by  Weed) 


178 


ELEMENTARY  ENTOMOLOGY. 


Fig.  267.   Three  common  pierid  butterflies 

(7,  native  cabbage  butterfly  {Foiitia  napi  oleracca), 

male;  /',  imported  cabbage  butterfly  {Pontia  rapae), 

female  ;  c,  the  common  sulphur  butterfly  {Emymiis 

philodke),  female.    (Photograph  by  Fiske) 


family  it  has  a  pair  of  pecu- 
liar, orange-colored,  mem- 
branous horns,  which  are 
protruded  from  between 
the  segments  close  to  the 
head  and  which  give  off 
quite  a  disagreeable  odor. 
Evidently  these  are  defen- 
sive organs,  for  they  appear 
only  when  the  caterpillar 
is  disturbed.  This  family 
includes  our  largest  and 
most  brilliant  butterflies. 
The  spring  and  summer 
broods  of  some  species  are 
so  differently  colored  that 
they  might  be  taken  for 
distinct  species. 

Pieridae.  The  family 
Picridac  includes  the  yel- 
low butterflies  (sometimes 
called  puddle  butterflies, 
from  their  habit  of  swarm- 
ing around  puddles)  and 
the  common  white  cabbage 
butterfly,  which  is  almost 
the  only  form  of  economic 
importance  in  the  family. 
The    larvae     are     slender 


green  caterpillars,  clothed  with  short,  fine  hairs, 
and  are  often  finely  striped,  resembling  the 
cabbage  worms.  The  larvae  of  the  common 
clouded  sulphur  {E?irymus  philodice)  feed  on 
clovers  and  leguminous  plants,  but  are  rarely 
numerous  enough  to  be  injurious. 

The  gossamer- winged  butterflies  (Lycaenidae), 
so  called  on  account  of  their  delicate  struc- 
ture, include  the  little  blue  and  copper-colored 


Fig.  ::6S.  The  common 

blue  butterfly  {Lycaena 

pseudargiolns     Boisd.), 

underside  of  female 

(After  Fiske) 


THE  BUTTERFLIES  AND  MOTHS 


179 


Fk;.  269.    The  bronze   copper 

butterfly     {Chrysopha>iiis    thoe 

Boisd.),  female 

(After  Fiske) 


butterflies  which  flit  along  the  road- 
sides in  spring.  Others  are  blackish 
or  bluish  above,  often  with  two  or 
more  fine,  threadlike  tails  extending 
from  the  hind-wings,  and  are  marked 
with  fine,  hairlike  streaks  on  the  under- 
surface,  which  has  given  them  the 
name  of  "  hair  streaks."  The  larvae 
are  quite  different  from  other  cater- 
pillars, being  flat,  elliptical  in  outline 
(with  the  head  retracted),  and  quite 
sluglike  in  appearance.  Very  few  of  them 
are  ever  injurious,  the  worst  offender  being 
the  cotton-square  borer  {Uranotcs  melli- 
nns),  which  bores  into  cotton  squares  and 
occasionally  attacks  beans  and  cowpeas  by 
eating  into  the  pods. 

The  four-footed  butterflies  (Nymphalidae) 
include  most  of  our  common  larger  forms, 
and  are  so  called  on  account  of  the  great 
reduction  of  the  fore-legs  ;  this  makes 
them  of  no  service  in  walking,  and  the 
legs  are  folded  on  the  breast.  The  common  monarch,  or  milk- 
weed, butterfly  (Anosia 
plexippns),  whose  green, 
black-ringed  caterpillars 
feed  upon  the  foliage  of 
the  milkweed,  is  a  good 
example  of  the  family. 
The  spiny  elm  caterpil- 
lar, already  described  (see 
p.  63),  also  belongs  here. 
The  dark,  reddish-brown 
butterflies  of  the  hop  mer- 
chant {Polygonia  comma) 
are  of  interest,  for  when 
they  fold  their  ragged- 
edged  wings   and  alight 


Fig.  270.    The  acadian  hair- 
streak  (Thecla  acadica  Edw.), 
underside  of  female 

(Photograph  by  Fiske) 


Fig. 


71.     The    cotton    square-borer    {L'ranotes 
melliniii).    (All  somewhat  enlarged) 

a,   dorsal   view  of  butterfly ;    b,  butterfly  with  wings 

closed;  c,  larva  (side  view)  ;  J,  pupa.    (After  Howard, 

United  States  Department  of  Agriculture) 


Fig.  273.    The  viceroy  butterfly  (Ba- 


Fig.  272.    The  monarch  butterfly  (Anoiia        silarchia  archippus)  and  its  chrysalis. 
plexippus)  on  thistle.    (Reduced)  (Reduced) 

(Photograph  by  Weed)  (Photograph  by  Weed) 


Fig.  274.    Caterpillar  and  chrysalis  of  the  monarch  butterfly 
(Photograph  by  Weed) 

180 


Fig.  276.    The  myrina  butuill)-  {Ar- 
gynnis  myrina  Cramer),  male 

(After  Fiske) 


Fig.  275.    Caterpillar  of  the  viceroy 
butterfly.    (Reduced) 

(Photograph  by  Weed) 


L//       '  "<-►■; 


Fig.  277.    Harris's  butterfly  {McUtaea 
harrisii  Scud.),  undersurface,  male 

(Photograph  by  Fiske) 


Fig.  278.    The  tharos  butterfly  {Phy- 

ciodes    tharos    Dru.),    female,    upper 

and  under  surfaces 

(After  Fiske) 


Fig.  279.    The  American  tortoise  butterfly  [Vanessa  milberti  Godart),  upper  and 

under  surfaces 

(After.Fiske) 

iSi 


I«2 


ELEMENTARY  ENTOMOLOGY 


Fig.  2^ 


Hunter's   butterfl\-    (jyi-aiiu 
Fab.),  male 

(After  Fiske) 


I  III  lit  era 


among   dead    leaves,    as    they    frequently    do    when    pursued    in 

woodland,  the  underwings  so  closely  resemble  the  leaves  as  to 

make  them  quite  indis- 
tinguishable. A  bright, 
silvery  comma  is  seen 
on  the  underside  of 
each  hind-wing,  which 
gives  the  specific  name. 
The  larvae  are  red- 
dish or  yellowish,  with 
black  head  and  black- 
j  branched  spines  ;  they 
feed  on  elm  and  net- 
tles, though  they  are 
better  known  as  pests 
of  the  hop-vine. 
The  dull,  grayish-brown  butterflies,  with  numerous  eyespots  on 

the  borders  of   their  wings,   which    flit  through  our  woodlands 

like  changing  shadows,  are  known 

as  meadow-browns,  or  satyrs,  and 

also  belong  to  this  large  family. 

The  larvae  of  the  more  common 

species  feed  on  grass,  and  may  be 

recognized  by  the  caudal  segment 

being  bifurcated. 

The  fritillaries,  or  argynnids,  are 

another  group  of  common  butter- 
flies included  in  this  family.   They 

are  usually  of  medium  size,  of  a 

golden-brown   color,   marked  with 

rows  of  black  spots  above  and  with 

bright,  silvery  spots  on  the  under- 

surface.    There  are  several  species 

which  are  very  difficult  to  distin- 
guish, and  whose  caterpillars  feed 

on    violets.       One    of    the     smaller       fk,  ^gi.    Hunter's  butterfly  at  rest, 
species,  very  similar   to  the   larger         showing  underwing  and  chrysalis 
forms,   is    illustrated    in  Fig.   276,  (Photograph  by  weed) 


THE   BUTTERFLIES  AND  MOTHS 


183 


Moths 

The  moths   fly  by  night,   are  readily  attracted   to   Hghts,   and 
are    often    called   millers.     When   at   rest  the   wings   are   folded 

upon  or  around  the 
abdomen.  The  an- 
tennas are  thread- 
like or  feathered, 
but  are  never  en- 
larged at  the  tip. 

In  striking  con- 
trast to  the  butter- 
flies, most  of  our 
moths  are  little  in 
evidence,  but  al- 
most all  of  their 
caterpillars  are  in- 
jurious and  require 
incessant  fighting 
to  control  them. 
No  attempt  will  be  made  to  indicate  the  natural  relationships 
of  the  families,  which  will  be  grouped  and  described  in  such  a  way 
as  to  best  aid  in  their  recogni- 
tion. Several  of  the  more  un- 
common families  have  been 
purposely  omitted  from  the 
discussion. 

Three  large,  nearly  related 
families  of  small  moths  are 
commonly  grouped  together  as 
Microlepidoptera,  on  account  of 
their  relatively  small  size  in 
contrast  to  the  remaining  fam- 
ilies.  The  laro^er  moths  and  the 


Fig.  282.    The  white-banded  purple  butterfly  {Linieiiitis 
arthemis  Dru.),  male 

(After  Fiske) 


Fig.  283.   The  canthus  butterfly  'T  c\cd 

brown  [Xeoiivinpha  caitthiis  Boisd.  and 

Lee),  undersurface 

(After  Fiske) 


butterflies  are  termed  Macrolepidoptera.  This  grouping  together 
of  the  larger  and  smaller  moths  is  a  classification  for  the  conven- 
ience of  the  collector  and  is  not  based  on  any  specific  difference 
of  structure. 


1 84 


ELEMENTARY  ENTOMOLOGY 


MICROLEPIDOPTERA 


The  tineids  (Tineidae)  are  our  smallest  moths  and  may  be  dis- 
tinguished by  the  long,  narrow  wings  having  a  broad  fringe 
of   hair,    particularly   on   the   hind-wings,   which   are   often   very 


Fig.  284.    A  tineid  leaf-miner  of  the  oak  {[Jthocolletis  hamaihyadella) 

a,  I),  larva,  flat  and  round  forms  ;  c,  pupa  ;  d,  moth  ;  c,  oak  leaf  showing  mines,  with  cocoons 
sxf,f.    (After  Comstock) 


narrow,  with  a  fringe  several  times  as  broad.    Many  of  the  larvae 
are  leaf-miners,  feeding  between  the  surfaces  of  leaves,  in  which 

they  tunnel  out  mines 
whose  shape  is  charac- 
teristic of  the  species; 
some  are  linear,  others 
serpentine,  some  are 
trumpet-shaped,  while 
others  are  irregular 
blotches.  These  little 
larvae  are  usually  white, 
and  are  very  much 
flattened,  with  small, 
wedge-shaped     heads, 


Fig.  285.    The  apple  leaf-miner.    (Greatly  enlarged) 

a,  moth  ;  b^  moth  at  rest ;  c,  larva  ;  d,  pupa.    (After  Quain- 
tance,  United  States  Department  of  Agriculture) 


THE  BUTTERFLIES  AND  MOTHS 


185 


with  only  rudiments  of  legs,  and  with  the  abdomen  constricted 
between  the  segments.     Many  of  them   hibernate  in  the  fallen 


Fig.  286.    The  cigar  case-bearer.    (Much  enlarged) 

a,  female  moth  ;  /',  side  view  of  pupa  ;  r,  larva ;  d,  egg  ;  e,  wing  venation  ;  /,  upper  view  of 
cigar-shaped  case  with  three-lobed  opening  at  tip  ;  g^  side  view  of  same  ;  li,  the  case  as  it 
appears  in  the  spring ;  /,  the  fall  and  winter  case.    (After  Hammar,  United  States  Depart- 
ment of  Agriculture) 

leaves,  in  which  they  pupate  and  transform  the  next  summer.  A 
well-known  example  is  the  apple-leaf  trumpet  miner  {TiscJieria 
malifoliella),  whose  brown,  trumpet-shaped  mines  are  common  in 
apple  leaves  and 
often  cause  con- 
siderable damage. 
Some  of  the  cat- 
erpillars of  this 
family  make  little 
cases  of  silk,  in 
which  they  reside 
and  which  are 
carried  over  the 
abdomen  as  they 
feed  on  the  foli- 
age, much  like 
the    shell    of    a 

snail.    Common  examples  are  the  pistol-case  bearer  and  the  cigar- 
case  bearer,  which  are  common  on  apple  foliage  and  are  so  named 


F"iG.  287.  The  case-making  clothes  moth  {Tinea 
pellioitella).     (Enlarged) 

ix,  adult  ;  /',  lar\-a  ;  c,  larva  in  case.    (After  Riley) 


1 86 


ELEMENTARY  ENTOMOLOGY 


Fig.  288.    The  angumois  grain-moth  [Sitotroga  cerealella 
01.).    (Enlarged) 

rt,  eggs  ;  b,  larva  at  work  ;  f,  larva  ;  d,  pupa  ;  ^,  /",  moth.    (After 
Chittenden,  United  States  Department  of  Agriculture) 


from  the  shapes  of  the  cases.    Nearly  related  to  them  are  the  little 
clothes  moths,  the  plague  of  every  housekeeper,  which  feed  on 

woolens,  furs,  etc. 
There  are  several 
species :  one  makes 
a  case  of  bits  of 
food  fastened  to- 
gether with  silk, 
another  builds  a 
tube,  and  a  third 
feeds  unprotected. 
The  more  common 
forms  are  of  a 
brown  color  and 
may  be  distin- 
guished from  other 
small  moths  which 
frequent  the  house 
by  the  broad  fringe  to  the  wings  already  mentioned.  Another  mem- 
ber of  this  family  which  is  a  serious  pest  of  stored  corn  in  the 
South  is  the  angumois  grain-moth 
{GclecJiia  cerealella),  whose  larvae 
live  in  the  kernels  of  corn  and  annu- 
ally destroy  millions  of  dollars'  worth. 
The  leaf -rollers  {Tortricidae).  Here 
and  there  on  various  shrubs  and 
plants  will  be  found  leaves  which 
have  been  rolled  up  and  fastened 
together  with  silk  by  a  little  cater- 
pillar living  within.  Most  of  this  is 
done  by  the  leaf-rollers,  which  are 
the  most  characteristic  of  the  family 
Tortricidae,  though  by  no  means  all 
leaf-rollers  belong  to  this  group.  The 
oblique-banded  leaf -roller  {ArcJiips 
rosaceana)  is  found  commonly  on 
roses  and  various  fruit  trees,  occa- 
sionally becoming  injurious,  while  its 


■Bfrf    ^<^ 


Fig.  289.   The  oblique-banded  leaf- 
roller  {Archips  rosaceana).  (Slightly 
enlarged) 

a,  egg-mass  ;  l>,  larva ;  r,  pupa ;  d,  female 
moth  ;  c,  male  moth 


THE  BUTTERFLIES  AND  MOTHS 


187 


near  relative,  the  cherry-tree  leaf-roller  (A.  ccrasivorana),  festoons 
the  branches  of  the  wild  and  cultivated  cherries  with  its  large  nests 
of  leaves  fastened  together  with  silk,  in  which  a  whole  brood  of 
the  yellow  larvae  live  and  transform.  Another 
group  of  this  family  includes  the  well-known 
codling  moth  (Cydia  povwnclla),  the  worst  pest 
of  the  apple  grower,  and  the  eye-spotted  bud 
moth  [Tnictoccra  occllana),  which  bores  in  the 
young  buds 
of  the  apple, 
as  well  as  nu- 
merous other 
larvae  which 
bore  in  the 
buds,  termi- 
nal twigs, 
fruits,  and 
seeds  of  va- 
rious trees 
and  plants. 

The  pyralids.  The  third  family,  Pymlidae, 
includes  some  half  dozen  families  of  quite  di- 
verse appearance  and  habits,  among  which  are 
the  larger  "micros,"  some  of  the  largest  having 
a  wing  expanse  of  one  and  one  half  inches  and 
being  larger  than  the  smaller  forms  of  the 
macrolepidoptera.  Many  of  the  caterpillars  be- 
longing to  this  group  attack  low-growing  vegeta- 
tion, the  garden 
web-worm  {Lo- 
xostege  siniila- 
lis)  being  one 
which  now  and 
then  becomes  a 
pest  in  various 
parts  of  the  country,  attacking  gar- 

1  1,1  Fig.  2Q2.    Codling-moth  larva  in  its 

den  crops,  sugar  beets  and  young     ,,i,,ter  cocoon  under  a  bit  of  bark 
cotton,  and  corn.     The  full-grown  (Enlarged  and  natural  size) 


Fig.  291.    The  codling  moth.    (Enlarged) 
(After  Slingerland) 


Fig.  290.  Web  and 
empty  pupal  skins 
of  the  cherry  leaf- 
roller  [Archips  cerasi- 
vorana).    (Reduced) 

(Photograph  by  W'eed) 


1 88 


ELEMENTARY  ENTOMOLOGY 


caterpillars  are  slightly  over  an  inch  long,  yellowish  or  yellowish- 
green,  marked  with  numerous  shining  black  tubercles  or  warts, 

and  may  be  recog- 
nized by  the  fine 
web  which  they  spin 
over  the  food.  The 
moths  are  of  a 
yellowish-buff  color, 
with  darker  mark- 
ings (see  Fig.  293). 
The  melon  caterpil- 
lar and  the  pickle- 
worm  ( DiapJiania 
hvalinata  and  iiiti- 
dalis)  are  serious  crop 
pests  in  the  Gulf 
States,  though  they 
occur  farther  north  and  in  the  West.  The  caterpillars  are  about 
an  inch  long,  yellowish  or  greenish-yellow,  and  feed  on  the  foliage, 
flowers,  and  fruit.    Among  the  typical  pyralids  is  the  clover-hay 


Fig.  293.    The  garden  web-worm  (Loxostet^'c  siniilalis) 

a,  male  moth  :  b,  larva,  lateral  view :  c,  larva,  dorsal  view ;  </, 
anal  segment ;  c,  abdominal  segment,  lateral  view  ;  /,  pupa ; 
g,  cremaster.  a,l'.c,f,  somewhat  enlarged;  d,c,g,  more  en- 
larged. (After  Riley  and  Chittenden,  United  States  Depart- 
ment of  Agriculture) 


Fig.  294.    The  meal  snout-moth  (Pyralis  farhialis  Linn.).    (Twice  natural  size) 

a,  adult  moth  ;  b,  larva ;  c,  pupa  in  cocoon.    (After  Chittenden,  United  States  Department 

of  Agriculture) 


worm  {Pyralis  costalis),  which  is  abundant  in  stacks  or  mows  of  old 
clover  hay,  upon  which  it  feeds  and  which  is  spoiled  by  being  cov- 
ered with  its  silken  webs  and  excrement.   The  moth  is  of  a  lilac 


THE  BUTTERFLIES  AND  MOTHS 


189 


color,  with  golden  bands  and  fringes,  and  expands  four  fifths  of 
an  inch.  The  meal  snout-moth  {Pyralis  farinalis)  also  sometimes 
feeds  on  clover  hay,  though  it  is  more  commonly  a  pest  of  meal  and 
flour,  in  which  it  spins  silken  tubes  wherever  it  feeds.   A  thorough 


Fig.  295.    The  Indian-meal  moth  (F/odia  interpunctella).    (Enlarged) 

(7,  moth;   /',  pupa;   r, /,  caterpillar;  d,  head;   e,  first  abdominal  segment  of  same.    (After 
Chittenden,  United  States  Department  of  Agriculture) 


cleaning  out  of  barns  and  grain  rooms  will  usually  prevent  trouble 
from  both  of  these  pests. 

The  subfamily  PJiycitinac  includes  another  pair  of  pests  of  grain 
products,  —  the  Indian-meal  moth  {Plodia  interpu7ictelld),  whose 
white  larvcC  spin 
silken  tubes  in 
meal,  dried  fruits, 
and  other  stores 
which  they  infest, 
and  the  Mediter- 
ranean flour-moth, 
which  has  similar 
habits  and  has  be- 
come a  very  serious 
pest  of  flour  mills, 
clogging  up  the 
machinery  with  its 
strong  silken  webs  and  necessitating  frequent  fumigation.  The' only 
common  representative  of  another  family  is  the  bee-moth,  whose 
larvae  feed  upon  the  wax  of  honeycombs,   in  which   they  make 


Mediteranean     flour-moth     [Epheslia 
kuefnticUa) 

n,  6,  moth  ;  c,  larva;  d,  pupa  (enlarged);  c,  abdominal  segment 

of   larva   (more  enlarged).    (After  Chittenden,   United   States 

Department  of  Agriculture) 


190 


ELEMENTARY  ENTOMOLOGY 


silk-lined  galleries,  destroying  the  combs.  They  attack  weak  colo- 
nies of  bees,  which  they  frequently  destroy,  and  are  one  of  the 
worst  enemies  of  the  apiary.  The  moth  has  purplish-brown  fore- 
wings  and  brown 
or  faded  yellow 
hind- wings. 

The  close-wings 
{C?'a)nbijiac)  are 
so  called  because 
their  wings  are 
wrapped  closely 
about  them  when 
at  rest.  They  are 
also  called  snout- 
moths.  They  are 
the  small  brown- 
ish or  silvery- 
white  moths  which 
fiy  up  before  us 
in   pastures   and 

are  scarcely  distinguishable  from  the  grass  stems  on  which  they 
alight.  The  larvae  feed  on  the  roots  and  stalks  of  grasses,  living 
in  little  tubes  constructed  of  bits  of  earth  and  vegetation  fastened 
together  with  silk.  Several  spe- 
cies are  sometimes  quite  injurious 
to  young  corn  planted  on  land 
where  they  have  been  abundant, 
the  most  common  being  known 
as  the  corn-root  web- worm. 

Two  other  families  of  this  group 
are  known  as  plume-moths  {Ptero- 
phoridae  and  Orneodidae),  as  the 
wings  are  split  into  parts  looking 
like  a  small  fan  of  feathers.  The 
larvae  of  one  species  occasionally 
webs  up  the  terminals  of  young  grape  shoots,  and  another  species 
is  sometimes  common  on  sweet-potato  vines,  but  they  are  rarely 
of  economic  importance. 


Fig.  297.    A  crambid  moth  [Crainbin  7<u!i;ivai^clliis) 

a,  larva  ;    /',  overground,  and  c,  underground,  tube  and  cocoon  ; 

if,  e,  /.  moths  with  wings  open  and  at  rest ;  g,  egg  much  enlarged. 

(After  Riley) 


Vic. 


29S. 
moth 


A    California    plume- 
(Natural  size) 

(After  Kellogg) 


THE  BUTTERFLIES  AND  MOTHS 


191 


MACRO  LEPIDOPTERA 


Among  the  larger  moths  are  two  famihes  whose  larvae  bore  into 
solid  wood,  though  they  are  by  no  means  nearly  related. 

The  carpenter-moths  (Cossidae)  are  medium-sized  to  large  moths 
with  spindle-shaped  bodies  and  strong,  narrow  wings,  thus  closely 


Fig.  299.    The  leopard  moth.    (Natural  size) 

a,  female  moth  ;   3,  male  moth ;  c,  larva  in  burrow ;  d,  pupal  skin  from  which  moth  has 
emerged.    (From  Insect  Life,  United  States  Department  of  Agriculture) 

resembling  the  sphinx  moths.  The  caterpillars  are  all  wood  borers, 
living  from  two  to  four  years  in  the  roots  or  trunks  of  trees.  When 
full  grown  they  are  from  two  to  three  inches  long,  usually  whitish, 
more  or  less  black-spotted,  with  black  heads  bearing  strong  jaws. 
The  female  moth  of  a  common  species,  which  lives  in  the  locust, 
has  a  wing  expanse  of  three  inches  and  is  of  a  pepper-and-salt 
color.    A  recently  imported  European  species  is  the  leopard  moth 


192 


ELEMENTARY  ENTOMOLOGY 


{Zaizera  pyrina),  which  is  seriously  damaging  the  shade  trees 
of  Eastern  cities  to  which  it  has  spread.  It  is  white,  spotted  with 
numerous  black  spots. 

The  clear-winged  moths  (Sesiidae).  The  caterpillars  of  the  clear- 
winged  moths  also  bore  into  the  trunks  and  roots  of  trees  and  the 
stalks  of  smaller  plants.  The  wings  of  the  moths  are  quite  narrow 
and  are  free  from  scales  except  along  the  margins  and  over  the 


Fig.  300.    Peach-tree-borer  moths.    (Natural  size)  , 

The  upper  one  and  one  at  right  are  females,  the  other  two  are  males.    (After  Slingerland) 


veins,  leaving  them  quite  transparent.  The  antennae  are  long,  and 
the  body  is  long  and  slender,  the  abdomen  being  commonly  banded 
with  yellow  and  terminating  in  a  tuft  of  scales.  Unlike  most  moths 
they  are  found  frequenting  flowers  in  the  daytime,  and  may  very 
readily  be  mistaken  for  wasps,  which  they  seem  to  mimic.  The 
best-known  example  of  the  family  is  the  peach-tree-borer  {Sanni- 
noidea  cxitiosa),  whose  white  larvae  bore  into  the  lower  trunks  and 
roots,  being  probably  the  worst  insect  enemy  of  the  peach  tree. 
The  males  are  black  with  narrow  yellow  bands  on  the  abdomen, 


THE  BUTTERFLIES  AND  MOTHS 


193 


and  with  quite  transparent  wings,  while  the  females  are  much 
larger,  having  fore-wings  of  a  blackish  brown  and  entirely  covered 
with  scales,  and  a  black  abdomen  with  a  broad  orange  band  about 
the  middle.  Other  injurious  species  of  clearwings,  smaller  and 
more  wasplike  than  the  peach-borer,  are  the  currant-borer  {Scs/a 
tip7diformis),  the  raspberry  root-borer  {Bcnibccia  niarginata)^  and 
the  well-known  squash-vine  borer  {Mclittia  ccto)  whose  whitish 
larvae  bore  through  the  vines  of  squash  and  other  cucurbits,  often 
mining  the  crops.    Not  all  clear-winged  moths  belong  to  this  family, 


Fig.  301.    The   squash-borer   (Melittia  saiyrinifo7-i7iis   Hbn.)-     (Enlarged 

one  third) 

rt,  male  moth ;  b,  female  with  wings  closed  ;  c,  eggs  on  squash  stem  ;  </,  larva ; 
^,  pupa  ;  /,  cocoon 


for  a  few  of  the  sphinx  moths  (which,  however,  are  much  larger) 
and  one  or  two  other  families  have  species  with  wings  almost 
wholly  free  from  scales. 

The  prominents  (Notodontidae)  are  dull-colored,  medium-sized 
moths,  with  a  wing  expanse  of  from  one  and  one  fourth  to  two 
inches,  many  of  whose  larvae  bear  strong  humps  or  prominences 
which  may  have  given  rise  to  the  common  name  of  the  family. 
The  moths  quite  closely  resemble  the  owlet  moths,  from  which  they 
can  be  distinguished  only  by  an  examination  of  the  wing  venation. 
The  handmaid  moths  are  of  a  reddish-brown  color,  with  the  fore- 
wings  crossed  with  several  darker  brown  lines,  whose  larvae  have 
the  peculiar  habit  of  raising  the  head  and  tail  and  standing  quite 


194 


ELEMENTARY  ENTOMOLOGY 


motionless  when  disturbed,  as  shown  in  the  ihustration  (Fig.  302) 

of  the  common  yellow-necked  apple  caterpillar  {D  at  ana  luiuistra), 

the  specific  name  of  which  has 
given  the  group  the  common 
name  of  "handmaids."  It  is 
common  on  apple  trees  in  late 
summer,  the  colonies  of  cater- 
pillars stripping  the  foliage 
back  from  the  tips  of  the  twigs, 
and  may  be  readily  recognized 
by  the  black  head,  yellow  neck, 
and  black-and-yellow  striped 
body.  Nearly  related  species 
of  blackish  caterpillars  covered 
with  gray  hairs  often  defoliate 
the  hickory.  The  red-humped 
apple  caterpillar  (ScJiiziira  con- 
cinna)  is  associated  with  the 
above  species  on  the  apple 
and  has  very  similar  habits.  It 
is  of  a  yellowish-brown  color, 
pale    along   the    sides,    which 

are  marked  with  fine  black   lines  ;    the  head  is  red,  the  fourth 

segment  bears  a  prominent  red  hump,  and  along  the  back  there 

are      many      short 

spines.    Several  of 

the    caterpillars    of 

this     family     have 

irregular  humps  and 

prominences  along 

the   back    and  are 

of  a  green  color,  so 

that  as   they    feed 

on  the  edge   of  a 

leaf    they  are    not 

easily  distinguished       p^^  ^^^     ^^^^  red-humped  apple  caterpillar  feeding  in 
from      the      ragged  characteristic  position.    (Natural  size) 

leaf  edge.    Most  of  (After  Britton) 


Fu;.  ^02.   The  yellow-necked  apple  cater- 
pillar {^Datana  ministra).     (Larvae  natural 
size  and  moth  slightly  enlarged) 


THE   BUTTERFLIES  AND   MOTHS 


195 


Fig.  304.    Antlered  maple  worms  {Hetero- 

campa    giitii'itta),     shcrwnng    variation    in 

color  markings.    (Slightly  enlarged) 


our  commonest  species  feed 
on  shade  and  forest  trees,  but 
rarely  do  widespread  damage. 
An  exception  to  this  is  the  case 
of  the  antlered  maple  worm 
{Heterocampa  gutivitta),  which 
stripped  thousands  of  acres  of 
maple  and  beech  along  the 
mountain  sides  from  central 
Maine  southwest  to  the  Adiron- 
dacks  in  the  summers  of  1908 
and  1909.  These  caterpillars 
arc  bright  green  with  a  saddle- 
shaped  mark  of  purple,  and  when  just  hatched  from  the  eggs  have 
small,  branched  antlers  just  back  of 
the  head.  The  eggs  of  this  family 
are  laid  on  the  foliage  of  the  food 
plant,  and  the  larvae  descend  to  the 
ground  to  pupate,  the  pupae  usually 
remaining  in  the  soil  over  winter. 

The  measuring-worms  (family 
Geometridae)  are  the  caterpillars  of  a 
large  family  ;  they  have  but  one  or 
two  pairs  of  abdominal  prolegs,  so 
that  as  the  middle  of  the  body  is 
unsupported  they  are  unable  to  walk 
like  ordinary  caterpillars,  but  loop 
along  in  a  characteristic  fashion,  which  has  given  them  the  com- 
mon name  of  "  inch-worms  "  or 
"  measuring  worms."  Many  of 
them  will  stand  with  the  body 
stretched  out  stiff  and  motion- 
less, so  that  they  are  readily 
mistaken  for  broken  twigs  and 
are    probably    passed    over    by 

,,    ,     ,   ,         ,,  ,        birds  seeking  food.    Although 

Moth  of  the  red-humped  °  .     .  '^ 

oak  caterpillar  there  are  no  absolutely  distinc- 

(After  Weed)  tivc    characters    by    which    the 


Fig.  305.    Red-humped  oak  cater- 
pillars   {Symnierista   albifrons)    on 
oak  leaf.    (Reduced) 


.i 

k^' ' 

^ 

Hy 

Fig.  307.    Caterpillar  of  Nerice  bidentata  feeding  on  leaf,  showing  resemblance 
of  contour  to  edge  of  leaf 

(After  Packard) 


Fig.  308.    The  chain-dotted  geometer  feeding  on  sweet-fern.    (Slightly  reduced) 

196 


THE  BUTTERFLIES  AND  MOTHS 


197 


moths  may  be  readily  recognized,  their  slender  bodies,  small  heads, 
and  broad  wings,  which  are  usually  noticeably  thin  and  frail,  give 
them  a  characteristic  appearance.  They  frequent  forests  and  edges 
of  woodlands,  and  though  a  few  are  orchard  pests,  and  others 
affect  the  bush  fruits, 
nearly  all  of  the  cater- 
pillars feed  upon  the 
foliage  of  forest  or 
shade  trees,  and  but 
few  frequent  low-grow- 
ing vegetation.  The 
moths  vary  from  less 
than  an  inch  to  over 
two  inches  in  wing 
expanse,  but  are  mostl)- 
of  medium  size.  The 
wings  remain  spread 
when  at  rest.  Possibly 
the  best-known  exam- 
ples are  the  canker- 
worms,  which  attack 
the  foliage  of  fruit  and 
shade  trees  in  early 
spring  and  drop  down 
from  the  trees  on  their 
silken  threads.  The 
females  of  the  canker- 
worms  and  some  nearly 
related  species  are  wing- 
less and  look  much 
more  like  fat  spiders 
than  moths.  The  chain- 
dotted  geometer  {Ciu- 
gilia  catenarid)  is  a  snow-white  moth  marked  with  zigzag  lines 
and  dots  of  black.  Its  larvae  feed  on  various  low-growing  shrubs 
and  trees  and  sometimes  appear  in  great  numbers,  as  was  the  case 
in  New  Hampshire  in  1906,  when  many  acres  of  sweet  fern  and 
scrub  birches  were  stripped.  The  larvae  are  of  a  bright  straw  yellow. 


Fig.  309.     The    chain-dotted    geometer    {Cingilia 

catenaria) ;   larva ;  larva  spinning  cocoon  ;   pupa  in 

cocoon  ;   moth.    (Slightly  enlarged) 


^^^^^^^K)^^^^k 

^_   '»     ^^^iB^       "^B 

O  ^^^3^^ 

^^^B              ^^S^K.^^^'  .^^^^^^^ 

"/ 

fl^^V^V^^^K^"^ 

mJ^^/^^^1^^^^^^^^ 

T 

i:r   <' 


THE  BUTTERFLIES  AND   MOTHS 


199 


^^a^ 


marked  with  six  black  lines 
and  with  a  black  dt)t  on  the 
side  of  each  segment.  The 
currant  span-worm  {Diastictis 
ribraria)  is  a  yellow,  black- 
spotted  looper,  which  often 
appears  in  such  numbers  on  cur- 
rant and  gooseberry  bushes  as 
to  defoliate  them  very  quickly. 

The  moths  are  pale  yellow, 
marked  with  irregular,  dusky 
spots.  Most  of  the  moths  of 
the  subfamily  Geovictriiiae  are 
of  a  green  color  with  the  wings 
barred  more  or  less  distinctly 
with  whitish  lines.  The  larvae 
of  one  of  these,  the  raspberry 
geometer  {SyncJilora  glau- 
caria),  feeds  on  the  fruit  and 
foliage  of  the  raspberry,  cover- 
ing itself  with  bits  of  vegetable 
matter,  thus  masking  itself 
beneath  what  is  apparently  a 
little  heap  of  rubbish. 

The  owlet-moths  {Noctuidae) 
are  b)-  far  the  largest  family  of 
the  order,  including  some 
twenty-one  hundred  species, 
three  times  as  many  as  there 
are  North  American  species  of 
birds,"  and  form  the  great  bulk 
of  the  moths  commonly  taken 
by  collectors.  As  their  name 
indicates,  they  fly  by  night  (as  do  all  other  moths, 
for  that  matter)  and  are  frequently  attracted  to  lights, 
being  the  common  "  millers  "  of  popular  parlance. 
The)-  are  not  readily  distinguished  from  nearly 
related  families,  nor  are  the  species  recognizable 


Fig.    311 
moth    and    eg 
winged    male 
cankerworm. 


Adult    female 

gg   mass   and 

of    the    fall 

Natural  size) 


(After  Dritton) 


P"iG.3i2.  Canker- 
worms  in  charac- 
teristic attitudes. 
(Natural  size) 

(After  Bailey) 


200 


ELEMENTARY  ENTOMOLOGY 


■i?*^*^ 

.^' 

^.  *^ 

y^^*^ 

^  -  --^ws 

^                               y 

^'wL  ■  "t 

tv-  ^m  r 

w               ^ 

■t^  "'— JT 

%h 

%.**^ 

E^J 

c. 

^ 

\ 

■^ 

-  '  ■ 

Fig.  313.    Drasteria  erechtea,  female 


except  by  an  expert,  though  many 
of  their  caterpillars  are  the  worst 
pests  of  the  farm  and  garden  and 
are  well  known  as  such  to  the 
farmer.  The  moths  are  mostly 
somber  gray  or  brown,  with  a 
wing  expanse  of  from  one  to 
three  inches  (averaging  about  one 
and  one  half  inches),  and  with 
stout  bodies.  The  fore-wings  are 
rather  narrow,  short,  and  stout,  crossed  by  darker  or  lighter  wavy 
lines,  and  with  one  or  two  darker  or  lighter  spots  toward  the 
center.  The  hind-wings  are  usually  plain,  and  when  at  rest  are 
concealed  by  the  fore-wings,  which 
cover  them,  either  flat  on  the  back 
or  slightly  roof-shaped.  Some  of 
the  caterpillars  are  hairy  like  the 
"  woolly  bears,"  but  most  of  them 
are  smooth,  dull-colored  "  worms," 
obscurely  striped,  as  are  the  com- 
mon cutworms.  Almost  all  of  the 
larvae  feed  on  low-growing  vegeta- 
tion and  pupate  in  the  ground. 
Among  the  moths  most  often  observed  are  those  of  the  northern 
grass  worm  {Drasteria  erechtea).  They  are  the  common  moths 
with  drab-gray  fore-wings,  crossed  with  two  dark  bands,  which  fly 
up  as  one  crosses  a  meadow  or  pasture.   The  larvae  are  green, 

narrowly  striped,  and 
are  semiloopers,  some- 
what resembling  the 
measuring  worms  in 
their  gait.  They  feed  on 
clover,  but  rarely  become 
injurious.  The  common 
cutworms  which  attack 
garden  and  field  crops 
Fig.  314  <5.    Army-worms.    (Natural  size)  throughout  the  country 

(After  Weed)  are  the  larvae  of  numerous 


Fig.  314  a.    Moth  of  the  army-worm 
{Leitcania  icnipiincta).    (Natural  size) 

(After  Riley) 


Fig.  315.    The  cotton  bollworm,  or  corn-ear  worm  [Hcliothis  cbsoleta). 
(Natural  size) 

rt,  adult  moth  ;  b,  dark  full-grown  larva  ;  c,  light  full-grown  lar\'a  ;  </,  pupa.    (.After  Howard, 
United  States  Department  of  Agriculture) 


/ 


Fig.  316.    The  cotton-boll  cutworm  {Prodenia  oriiithogalli  Guen.).    (Enlarged) 

«,  dark  form  of  male  moth  ;   b^  pale  form  of  female  moth  ;  c,  pale  form  of  lar\a ;  </,  dark 

form  of  same  ;  c^  lateral  view  of  abdominal  segments  of  dark  form  ;  /,  of  pale  form.    (.After 

Chittenden,  United  States  Department  of  Agriculture) 

201 


202 


ELEMENTARY  ENTOMOLOGY 


Fig.  317.    The  dark-sided  cutworm 
{Agrotis  7nesso7-ia) 

(After  Riley) 


species  of  moths  of  this  family,  be- 
longing to  several  genera.  The 
army-worm  lyLeiicania  iinipiiiicta) 
is  another  caterpillar  which  or- 
dinarily feeds  unnoticed  on  rank 
grasses,  but  occasionally  becomes 
very  numerous  and  advances  in 
armies,  destroying  all  crops  in  its 
line  of  march.  The  fall  army- worm 
{Laphygvia  frngipci-da)  has  very 
similar  habits,  but  is  more  common 
in  the  South  and  West.  Two 
of  the  most  serious  cotton  pests  are 
the  leaf  worm  {Alctia  argil  I  a  ci a) 
and  the  bollworm  {Hcliothis  obso- 
leta),  although  the  latter  also  attacks  the  ears  of  corn,  tobacco,  and 
green  tomatoes  throughout  the  Middle  States.    A  common  pest  of 

cabbage  and  lettuce  is 
the  cabbage  looper  {A  u- 
tographa  bj'assicac),  a 
bright  green  worm  with 
whitish  lines,  which 
bores  into  cabbages 
much  like  the  common 
caterpillars  of  the  cab- 
bage butterfly.  It  is 
known  as  a  looper  on 
account  of  the  way  in 
which  it  "humps" 
along,  much  like  a 
measuring  worm,  be- 
cause two  pairs  of 
the    usual    abdominal 

prolegs     are    lacking. 
Fig.  318.    The  cabbasre  looper  ^  r       i         i 

Some    of    the    larger 

a,  male  moth  ;  b,  egg  shown  from  above  and  from  side ;  .            r     1   •      r         -i 

c,  full-grown  larva  in  natural  position,  feeding  ;  d,  pupa  in  SpCClCS   01   iniS   lamuy, 

cocoon.   (7,  c,  d,  one  third  larger  than  natural  size  ;  /',  more  with    3.    wino"    expanSC 

enlarged.    (After  Howard  and  Chittenden,  United  States  ^     .                   ^             , 

Department  of  Agriculture)  Ot     trom    tWO    tO    three 


THE  BUTTERFLIES  ANT)  MOTHS 


203 


inches,  of  the  genus  Catocala,  have  mottled  gray  fore-wings  which 
very  closely  resemble  the  bark  of  trees,  upon  which  they  rest  during 

the  day.  The  hind- 
wings  are  black,  bril- 
liantly banded  with  red 
or  yellow.  They  are 
much  fancied  by  col- 
lectors and  are  taken 
by  luring  them  with 
sugar  water  or  similar 
lures,  smeared  on  the 
trees. 

The  tussock-moths 
(Liparidae).  The  cater- 
pillars of  the  tussock- 
moths  are  strikingly 
clothed  with  tufts  of  bright-colored  hairs,  or  tussocks,  which  has 
given  them  their  popular  name.  The  moths  are  medium  sized, 
usually  of  a  dull  brown  or  gray  color.    The  males  have  feathered 


Fig. 


519.    Catocala  nit  ran  ia  and  its  larva 
(After  J.  B.  Smith) 


Fig.  320.    The  white-marked  tussock-moth.    (Natural  size) 
«,  wingless  females  depositing  eggs  on  cocoons ;  b,  male  moths  ;  c,  full-grown  female  larva 


204 


ELEMENTARY  ENTOMOLOGY 


'^ 


:r> 


antennae.  The  females  of  our  common  species,  of  which  the 
white-marked  tussock-moth  i^Hcincrocampa  leucostigma)  is  a  good 
example,  are  wingless  and  look  more  like  hairy  grubs  or  fat 
spiders  than  moths.  These  wingless  females  pair  as  soon  as  they 
emerge  from  the  cocoons,  and  then  lay  their  eggs  upon  them  and 
die.  The  eggs  of  this  species  are  usually  found  on  the  trunks  of 
trees,  and  are  covered  with  a  white  substance  looking  like  frosting. 

The     caterpillar     is 
'  about   one    and   one 

half  inches  long,  with 
a  pair  of  black  pencils 
of  hairs  projecting  a 
half  inch  forward  on 
either  side  of  the  head, 
and  a  single  pencil  of 
similar  length  extend- 
ing from  the  tip  of 
the  abdomen.  The 
head  and  a  small 
glandular  dot  on  the 
center  of  the  sixth 
and  seventh  abdom- 
«.  -  «.T7«>  '  •  inal     segments     are 

^^E  Vf  bright  red,  the  body 

^^■^K  -^  is  yellow  banded  with 

^^^^^  black,  and    the    first 

four  abdominal  seg- 
ments bear  brushlike 
tufts  of  white  hairs. 
This  species  often  becomes  a  serious  pest  of  shade  and  fruit  trees, 
while  nearly  related  species  are  common  but  not  so  injurious.  To  this 
family  belong  the  gypsy  moth  {Porthctria  dispar)  and  the  brown- 
tail  moth  {Ejiproctis  chryson'hoed),  both  of  which  have  been 
imported  from  Europe  into  New  England,  where  they  have  done 
enormous  damage  to  trees  of  all  kinds.  The  male  gypsy  moth  is 
tawny  brown,  with  black  markings,  while  the  female  is  much  larger, 
and  is  white,  with  wavy  blackish  lines  across  the  wings.  The 
female  is  unable  to  use  her  wings  for  flight,  and  lays  her  eggs  on 


■h 


Fig.  321.    Male  and  female  gypsy  moths 
size) 


(Natural 


(After  Forbush  and  Fernald) 


THE  BUTTERFLIES  AND  MOTHS 


205 


Fig.  322.    Gypsy-moth  caterpillars.    (Natural  size) 
(After  Britton) 


the  bark  near  the  cocoon.  The  caterpillar  is  two  and  one  half 
inches  long  when  full  grown,  of  a  dark,  sooty  color,  somewhat 
hair)',  and  with  a  double  row  of  five 
pairs  of  blue  and  six  pairs  of  red  tuber- 
cles down  the  middle  of  the  back, 
which  distinguish  it  from  all  other  com- 
mon caterpillars.  The  brown-tail  moths 
are  pure  white,  with  a  brown  tuft  of 
hairs  at  the  tip  of  the  abdomen,  more 
prominent  in  the  female.  Both  sexes 
are  strong  flyers  and  are  carried  readily 
by  the  wind.  The  eggs  are  laid  in  a 
mass  on  the  foliage  and  are  covered 
with  brown  hairs  from  the  tip  of  the 
female's  abdomen.  They  hatch  early 
in  August,  and  after  feeding  two  or 
three  weeks  the  little  caterpillars  draw     p,^^  .,._   ^nre  brown-tail  moth, 

the   leaves   together  at   the   tips  of  the      male  and  female.    (Natural  size) 


206 


ELEMENTARY  ENl'OMOLOGY 


Fig.  324.   The  brown-tail-moth  caterpillar, 
from  side  and  back.    (Natural  size) 


branches  with  strands  of  silk  and  in  them  spin  Httle  silken  cells, 
the  whole  forming  a  strong  web,  within  which  they  pass  the  winter 

and  emerge  to  complete  their 
growth  in  the  spring.  The 
caterpillars  defoliate  fruit  and 
shade  trees,  but  never  attack 
conifers,  as  do  the  partly  grown 
gypsy-moth  caterj3illars.  They 
are  one  and  one  half  inches 
long,  of  a  dark  brown  color 
marked  with  patches  of  orange, 
and  covered  with  numerous 
long,  barbed  hairs.  On  the 
side  of  each  segment  is  a 
characteristic  white  dash,  and  the  little  red  spots  characteristic  of 
this  family  are  found  on  the  center  of  the  sixth  and  seventh  abdom- 
inal segments.  The  tubercles  along  the  back  and  sides  are  thickly 
covered  with  short  brown  hairs,  the 
masses  having  a  velvety  appearance. 
These  are  the  nettling  hairs,  which, 
when  they  alight  on  the  skin,  produce 
an  eruption  very  similar  to  that  caused 
by  poison  ivy,  and  which  is  so  painful 
and  annoying  that,  where  the  cater- 
pillars become  abundant,  they  render 
life  miserable  for  the  inhabitants  dur- 
ing early  summer.  As  the  nests  of 
this  pest  have  been  imported  on  pear 
seedlings  by  nurserymen  in  almost 
every  state  during  the  past  two  years, 
it  will  be  remarkable  if  it  is  not  soon 
found  outside  of  New  England,  and 
should  be  constantly  watched  for,  so 
that  it  may  be  brought  under  control  at 
once  before  it  spreads.  This  family  is 
a  small  one,  and  has  almost  no  species 

r  •     •  ,  •       1  •  tit;-  321;.    Winter  web  of  the 

of  economic  importance  m  this  country      brown-tail-moth    caterpillars 
other  than  those  mentioned.  (Reduced) 


THE  BUTTERFLIES  AND  MOTHS 


207 


Fig.  326.   The  salt-marsh  caterpillar  (Estigt/iLiic  acraL-a),  one  of  the 
"  woolly  bears  " 

The  tiger-moths  (Arctiidae)  are  well  named,  for  many  of  them 
are  conspicuously  striped  or  spotted  with  orange,  red,  or  black. 
Among  the  larvae  are  the  well- 
known  hairy  "woolly  bears," 
which  crawl  across  the  walks 
in  late  fall  and  early  spring, 
faithful  harbingers  of  winter 
and  summer.  The  moths  are 
frequently  attracted  to  lights, 
when  their  brilliant  colors  al- 
ways command  attention.  On 
some  of  the  larvae  the  hairs 
are  massed  into  brushes  much 
like  those  of  the  tussock-moths, 
as  is  the  case  with  the  com- 
mon harlequin  milkweed  cater- 
pillar {Cj'cnia  eglc),  which   is 

Fig.  327.    The  hickory  tiger-moth  [Hale- 
sidoia  caryae)  and  its  larva 

clothed  with  tufts  of  orange,  black, 
and  white  hairs,  and  is  the  most 

Fig.  728.    The  common  red-and-black  ,         -n  ,1  ^^^ 

caterpillar  of  the  Isabella  tiger-moth     COmmon  caterpillar  on   the   milk- 

{Pyrrharctia  isabeiid)  wccd.    Our  most  common  species 

(After  comstock)  is  possibly  the  Isabella  tiger-moth 


208 


ELEMENTARY  ENTOMOLOGY 


{Pyrrharctia  isabclla),  whose  hairy  larva  is  reddish-brown  in  the 
middle  and  black  at  either  end.    It  does  but  litde  harm,  but  is  the 

species  commonly 
seen  on  walks  in 
fall  and  spring,  so 
that  it  is  well 
known.  The  fall 
web-worm  is  the 
common  caterpil- 
lar which  covers 
our  fruit  trees 
with  its  unsightly 
webs  in  late  sum- 
mer. The  moths 
are  pure  white  or 
spotted  with  black. 
The  caterpillars 
vary  from  yellow- 
ish to  blackish, 
with  darker  lines 
and  spots,  and  are 
covered  with  long 
hairs.  Most  of 
the  caterpillars  of 
this  family  feed  on 
low-growing  vege- 
tation and  weeds ; 
several  now  and 
then  become  over- 
abundant and  at- 
tack garden  crops. 


Fig.  329.    The  fall  web-worm.    (All  slightly  enlarged) 

(7,  light  form  of  full  grown  larva;  /',  dark  form  of  same  ;  r,  pupa  ; 
d,  spotted  form  of  moth.    (After  Howard,  United  States  Depart- 
ment of  Agriculture) 


The  hawk-moths  {Sphingidae)  are  sometimes  called  humming- 
bird moths,  for  the  larger  species  are  fully  as  large  as  a  humming 
bird,  with  three  to  five  inches  wing  expanse,  and  are  frequently 
found  hovering  over  petunias  and  similar  flowers  on  warm  summer 
evenings.  They  are  easily  recognized  from  their  long,  spindle- 
shaped  bodies,  strong,  narrow  wings,  and  thick,  prismatic  antennae, 
which  are  often  curved  back  at  the  tip,  forming  a  slight  hook.    The 


THE  BUTTERFLIES  AND  MOTHS 


209 


proboscis  is  very  long,  in  some  species  being  twice  as  long  as  the 
body,  and  is  coiled  up  under  the  head  like  a  watch  spring.  Many 
of  the  caterpillars  are  known  as  hornworms,  from  the  strong  horn 
on  top  of  the  last  segment,  which  is  quite  characteristic  of  the 
family,  though  in  some  cases  it  is  replaced  by  a  bright,  glassy 
eyespot.  "When  at  rest,"  says  Dr.  J.  B.  Smith,  "some  of  them 
have  the  habit  of  elevating  the  front  part  of  the  body  and  curling 
the  head  under  a  little,  giving  them  a  fancied  resemblance  to  a 

spJiinx,  and  from 
this  the  scientific 
name  has  been 
derived."  A  well- 
known  example 
of  this  family  is 
the  large  green 
tobacco  or  toma- 
to worm  {Phlege- 
thontiiis  q?nnq?ic- 
viacnlata),\N\\\ch. 
rags  the  foliage 
of  these  plants, 
and  is  the  tobac- 
co grower's  worst 
enemy.  It  has 
slanting  white 
stripes  along  its 
sides,  and,  when 
fully    grown,    is 

about  three  inches  long ;  then  it  goes  underground  and  transforms 
to  a  mahogany  brown  pupa  from  one  and  one  half  inches  to  two 
inches  long,  bearing  a  peculiar  handlelike  process  bent  back  from 
the  head,  which  has  given  it  the  names  of  "  jug-handle  grub  "  and 
"  hornblower."  The  pupae  remain  in  the  soil  over  winter,  and  the 
moths  emerge  the  next  spring,  there  being  two  broods  a  season  in 
the  North  and  three  or  four  in  the  South.  The  adults  are  among 
our  most  handsome  moths,  the  wings  expanding  from  three  to  five 
inches,  ashen-gray  in  color,  the  fore-wings  crossed  by  irregular 
darker  lines  with  a  white  spot  near  the  center,  and  the  hind-wings 


Fig.  330.    LarvcC  of  achemon  sphinx 

Above,  young  larva  with  head  extended  and  with  caudal  horn  (en- 
larged); below,  full-grown  larva  with  head  partly  drawn  in  (natural  size) 


Fig.  331.     Typical   sphinx   moths    [Deilcphila   lineata    P'ab.   above  and  F/ioliis 

achemon  below) 

(After  Lugger) 


Fig.  332.    Southern  tobacco-worm  moth.    (Natural  size) 
(After  Britton) 


THE   BUTTERFLIES  AND   MOTHS 


21  I 


banded  with  black  and  white,  while  along  the  sides  of  the  abdomen 
are  five  large  yellow  spots.  The  grapevine  hog  caterpillar  (A>/i- 
pelophaga  viyi'on)  is  typical  of  a  series  of  species  in  which  the 
caudal  horn  of  the  larva  is  lost  and  replaced  by  an  eyespot ;  the 
first  two  thoracic  segments  are  much  smaller  and,  with  the  head. 


Fig.  333.    Southern  tobacco-worm.    (Natural  size) 
(After  Britton) 

are  retracted  into  the  metathorax.  This  has  given  some  one  the 
idea  that  they  resemble  fat  porkers,  —  hence  the  name  "  hog  cater- 
pillars." This  larva  is  common  on  the  grape  and  woodbine  and  is 
about  two  inches  long,  with  a  row  of  seven  reddish  or  lilac  spots  set 
on  a  yellow  background  along  the  middle  of  the  back,  and  a  white 

stripe  down  each  side,  below 
which  are  seven  oblique  stripes. 
It  is  quite  variable  in  color 
and  is  very  commonly  infested 
with  braconid  parasites  (see 
page  251),  whose  cocoons  are 
frequently  found  covering  the 
caterpillars.  Some  of  the 
smaller  moths  of  this  family 
have  the  wings  nearly  bare 
of  scales,  like  the  clear-winged 
moths,  and,  like  them,  fly  around  flowers  during  the  day.  The  larger 
ones  are  often  called  humming-bird  hawk-moths,  while  the  smaller 


F'iG.  334.    A  clear-winged  sphinx  moth,  or 
bee-moth  {He maris  ihysbe) 


212 


ELEMENTARY  ENTOMOLOGY 


ones  look  quite  like  large  bumblebees.  They  are  readily  recognized  as 
belonging  to  this  family  by  the  form  of  the  body,  wings,  and  antennae. 
The  saturnians  (superfamily  Saturnoided)  include  some  forty-two 
species  of  our  largest  silkworm  moths,  divided  into  four  families, 
which  need  not  here  be  distinguished.  The  large,  brilliantly  colored 
larvae  are  readily  reared,  and  from  the  cocoons  are  secured  the 
handsome  moths  which  are  the  pride  of  every  collector.  The  males 
of  this  group  are  easily  distinguished  from  the  females  by  their 
broadly  feathered  antennae.    The  most  important  economic  species 


Fig.  335.    Life  history  of  silk  moth  [Bcnibyx  mori) :  adult ;  caterpillars  of  different 
ages;  silken  cocoons  ;  pupa;  eggs.    (Natural  size) 

(After  Jordan  and  Heath) 


of  the  group  is  the  silkworm  [Bonibyx  mori),  which  is  reared  in 
Europe  and  Asia  for  its  silk,  furnishing  all  the  silk  of  the  world. 
It  has  been  frequently  introduced  into  this  country,  but,  although  it 
can  be  grown  here,  its  commercial  culture  has  never  proved  suc- 
cessful. It  is  one  of  the  smaller  moths  of  the  group,  expanding  one 
and  one  half  inches,  the  wings  being  of  a  cream  color,  with  two 
or  three  brownish  lines  across  the  fore -wings.  The  larvae  are  of  a 
creamy  white  color  and  feed  on  the  leaves  of  the  mulberry.  Another 
small  species  which  often  defoliates  our  maples  is  the  green-striped 
maple-worm  {Anisota  riibicuiida).  The  caterpillars  are  one  and  one 
half  inches  long,  yellowish-green,  striped  with  eight  lighter  lines 


THE  BUTTERFLIES  AND  MOTHS 


213 


alternating  with  seven  darker,  almost  blackish 
lines,  with  two  prominent  black  horns  on  the 
thorax  and  a  double  row  of  short,  thick  spines 
along  either  side  of  the  body.  The  moths  are 
pale  yellow  banded  with  rose  color,  and  are  fre- 
quently taken  at  lights.  Nearly  related  species, 
whose  larvas  are  brownish  with  orange  markings 
and  similar  black  spines,  attack  the  oak  foliage. 
The  lo  moth  {A?itoincris  to)  is  one  of  the  larger 
forms,  with  a  wing  expanse  of  nearly  three 
inches,  the  fore-wings  of  the  males  being  a 
brilliant  yellow  color  and  those  of  the  female  a 
dark  purplish,  both  having  a  large  eyespot  on  the 
center  of  the  hind-wings.  The  full-grown  larva 
is  about  two  inches  long,  yellowish-green,  with  a 
broad  brown  or  reddish  stripe,  edged  with  white, 
along  either  side,  thickly  covered  with  black- 
tipped,   branched   spines    which   are    decidedly 

ftrl^e'd^Ipfe^wZ"     Prisonous.    The  polyphemus  moth  (7>/..r /./j- 

{Anisoia  rtihicitnJa)  pheiHits)  is  ouc  of  our  largest  and  handsomest 
species,    expanding  from   four   to   five   inches. 

It    is    of   a    yellowish    or    brownish    color,    with    a    dusky    band, 

edged  without  with  pink  along  the  margins  of  both  wings,  and 

with  a  prominent  e)-espot  at  the  middle  of  each  wing,  those  on 

the     hind-wings 

being    bordered 

by  a  large  bluish 

patch.  The  lar- 
vas feed  on  oak 

and  various  fruit 

and  shade  trees ; 

they    are    three 

inches   or  more 

in      length,      of 

a   bright    green 

color,    with    an 

oblique       yellow  Fig.  337.    The  lo  moth,  female.    (Natural  size) 

line   on  the  side  (After  Lugger) 


Fig.  338.    lo  moth  caterpillar  Fig.  339.    ']\'Ica polvphemits  caterpillar 


Fig.  340.    Telea polyphemiis  moth  and  cocoon.    (Reduced) 

(After  Lugger) 
214 


THE  BUTTERFLIES  AND  MOTHS 


215 


of  each  abdominal  segment,   and  with   numerous   small   orange- 
colored  tubercles  with  metallic  reflections.     The  cocoon   is   oval, 

usually  wrapped  in  a  leaf, 
and  is  attached  to  the 
twigs  of  trees  and  shrubs. 
The  luna  moth  {Ac  tin 
hma)  is  a  brilliant  green 
species  with  long  tails  pro- 
jecting from  the  hind- 
wings  ;  it  is  frequently 
attracted  to  lights  on  warm 
evenings  of  early  summer. 
Each  wing  bears  a  small 
eyespot,  and  the  anterior 
margin  of  the  fore-wings 
is  purplish.  The  larvae 
feed  on  the  leaves  of  wal- 
nut, hickory,  and  forest 
trees.  Possibly  our  most 
common  species  is  the 
cecropia  moth  {Saniia 
cecropia)  whose  long 
brown  cocoons  are  fre- 
quently found  on  fruit  and 
shade  trees.  The  moths 
are  a  dusky,  reddish  brown, 
and  may  be  readily  recog- 
nized from  Fig.  34 1 .  The 
caterpillar  is  three  or  four 
inches  long,  of  a  bright 
green  color,  with  six  prom- 
inent tubercles  on  the 
thoracic  segments,  —  the 
first  four  coral-red  and 
the  hinder  two  yellow,  — 
and  with  smaller,  similar  yellow  tubercles  on  the  back  of  the  abdom- 
inal segments.  They  feed  commonly  on  fruit  and  shade  trees,  but 
are  never  numerous  enough  to  do  much  damage.    The  cocoons  of  a 


Fig.  341.    The  cecropia  moth  {Samia  cecropia), 
larva,  cocoon,  and  moth  at  rest.    (All  reduced) 

(Photograph  by  A\'eed) 


2l6 


ELEMENTARY  ENTOxMOLOGY 


Fig.  342.    The  promethea  moth  [Callosamia  prornethia). 
(Reduced) 

(Photograph  from  hfe  by  Weed) 


Fig.    343.      Pendent 
cocoons    of    prome- 
thea moth.    (Greatly 
reduced) 


nearly  related  species  {Callosarnia  prometJiid)  hang  pendent  from 
the  twigs  of  wild-cherr)^,  ash,  willow,  and  other  trees.  Although 
many  attempts  have 
been  made  to  manu- 
facture the  silk  in 
the  cocoons  of  these 
native  species,  they 
have  so  far  been  un- 
successful. 

Our  common  tent 
caterpillar,  which  is 
fully  described  on 
page  57,  is  a  repre- 
sentative of  a  family 
of  this  group  {Lasi- 
ocampidae),  though 
much  smaller  in  size 
than  the  preceding, 
having  a  wing  ex- 
panse of  one  and  Fig.  344.  Luna  moth  [Adia  Itma).  (Reduced) 
one    half    inches.  (Photograph  from  life  by  weed) 


THE  BUTTERFLIES  AND  MOTHS  217 


Fig.  345.    Caterpillar  of  the  imperial  moth  (Basilona  imperialis).    (Natural  size) 


Summary  of  the  Lepidoptera 

Butterflies.    Day  flyers.    Antennae  clubbed.    Wings  held  vertically. 
Skippers  {Hcsperina).    Antennae  hooked. 
True  butterflies  (^Papilioitind). 

Swallowtail  butterflies  {Papilio/iidae). 

White  and  yellow  butterflies  {Pieridae), 

Gossamer-winged  butterflies  {Lycaenidae). 

Four-footed  butterflies  {Xynnphalidae). 
MoTH.s.    Night  flyers.    Antennae  not  clubbed.    Wings  held  flat. 
Microlepidoptera. 

Family  ( Tineidae).    Leaf -miners,  clothes  moths,  etc. 

Family  (Tortricidae).    Leaf -rollers,  bud-borers,  etc. 

Family  {Pyralidae).  Leaf-folders,  meal-worms,  close-wings,  bee-moth, 
etc. 
Macrolepidoptera  (in  part). 

Carpenter-moths  (Cossidae).    Larvae  wood  borers. 

Clear-winged  moths  {Sesiidae).    Larvae  wood  borers. 

Prominents  (Notodontidae). 

Measuring-worms  (family  Geoniefrhiac). 

Owlet-moths  {Noctuidae). 

Tussock-moths  [Lipai-idae). 

Tiger-moths  [Arctiidae). 

H  awk-moths  [Sp/u'/ij^'idae). 

Saturnians    (superfamily    Saturnoidea).      Silkworm    moths.      Tent- 
caterpillar  moths. 


CHAPTER  XIV 


FLIES,  MOSQUITOES,  AND  MIDGES  (DIPTERA) 

Characteristics.  Insects  with  one  pair  of  wings  borne  by  the  mesothorax; 
the  hind-wings  represented  by  a  pair  of  knobbed  threads,  called  halteres ; 
mouth-parts,  suctorial ;  metamorphosis,  complete. 

Ordinarily  all  sorts  of  small  insects  with  membranous  wings  are 
indiscriminately  called  ^Z/cj-,  and  the  term  "  fly  "  has  been  used  to 
form  part  of  a  compound  name  for  insects  of  several   different 

orders,  such  as  May- 
fly, sawfly,  gallfly, 
butterfly,  etc.,  but," 
considered  from  the 
entomological  stand- 
point, a  fly  is  a  two- 
winged  insect  of  the 
order  Diptcra.  With 
this  in  mind,  it  is  al- 
ways easy  to  distin- 
guish flies,  as  no 
other  order  has  a 
single  pair  of  wings 
(except  the  male  scale  insects),  and  the  name  of  the  order  becomes 
significant,  being  derived  from  dis  (two)  and  ptcron  (wing).  The 
hind-wings  are  replaced  by  a  pair  of  odd,  club-shaped  organs, 
called  balancers,  or  halteres,  which  seem  to  be  concerned  with  main- 
taining the  equilibrium  of  the  insect  and  are,  of  course,  peculiar 
to  this  order.  A  few  of  the  parasitic  families  are  wingless.  The 
mouth-parts  have  already  been  referred  to  (see  page  i8)  and 
are  fitted  for  sucking  the  juices  of  plants  and  animals,  though  in 
some  there  are  strong,  lancelike  mouth-parts  fitted  for  piercing, 
while  in  others  a  large,  fleshy  proboscis,  fitted  for  rasping  and 
lapping,  is  developed. 

218 


Fig.  346.    The  house-fly.    (Enlarged) 

a,  larva,  or  maggot;  b,  puparium  ;  c,  adult.    (After  Howard 
United  States  Department  of  Agriculture) 


FLIES,  MOSQUITOES,  AND  MIDGES 


219 


The  transformations  are  always  complete.  The  most  common 
larvae  are  termed  "maggots,"  and  are  headless  and  foodess,  white,  or 
light-colored,  tapering  to  a  point  at  the  head,  usually  with  a  horny, 
rasplike  feeding  organ  retruded  within  the  head,  though  many 
absorb  nutriment  from  the  surrounding  food  through  the  skin.  In 
other  larvae  the  head  and  mouth-parts  are  well  developed,  while 
some,  like  the  mosquito  wrigglers,  lead  a  most  active  life.  The 
pupas  are  usually 
naked  or  inclosed  in 
the  last  larval  skin, 
though  a  few  make 
cocoons.  Instead  of 
being  molted,  the 
last  larval  skin  of 
most  common  flies 
becomes  hard  and 
distended,  and  the 
pupa  separates  with- 
in it,  so  that  the  lar- 
val skin  practically 
forms  a  cocoon  for 
the  pupa  and  is 
known  as  a  pupa- 
rium,  which  looks 
much  like  a  large 
brown  or  black  seed. 

The  Diptera  is 
one  of  the  largest 
orders,  with  over 
five  thousand  species  in  this  country  (a  great  majority  of  which 
may  be  classed  as  injurious),  and  includes  many  serious  crop  pests 
and  most  of  the  insects  which  carry  disease.  The  different  fami- 
lies are  distinguished  by  the  structure  of  the  antennae  and  of  the 
wing  veins,  and  are  divided  into  two  suborders,  the  typical  Dip- 
tera {Diptera  gennina),  including  all  the  common  families,  and 
the  Pnpipara,  including  three  small  families  of  parasitic  species, 
mostly  wingless. 


Fig.  347.    A  crane-fly  [Tipiila  hebes  Loew) 

a,  larva,  or  meadow-maggot ;  b,  pupa  ;  c,  adult  male  fly. 
(After  Weed) 


220 


ELEMENTARY  ENTOMOLOGY 


-gjfc 


I.    Typical  Diptera  {Diptera  genuina) 

Disregarding  characters  of  the  puparium  which  are  not  readily 
observable,  the  typical  Diptera  are  divided  into  two  series  of  fami- 
lies, based  upon  the  length  of  the  antennae,  known  as  the  Long- 
horned  Diptera,  which  have 
more  than  five  antennal 
segments,  and  the  Short- 
horned  Diptera,  having  not 
more  than  five  segments. 

LONG-HORNED  DIPTERA 

{XEIMATOCERA) 

The  crane-flies  (Tipulidae) 

are  easily  recognized  by 
their  long,  slender  bodies, 
narrow  wings,  and  exceed- 
ingly long,  fragile  legs, 
which  characteristics  have 
given  them  the  name 
"  granddaddy-long-legs, "  a 
name  more  correctly  ap- 
plied to  the  harvestmen, 
which  are  round-bodied 
spiders  with  very  long  legs. 
The  maggots  of  crane-flies, 
sometimes  called  leather- 
jackets,  or  meadow-mag- 
gots, are  dirty  white,  with 
a  tough  skin,  and  feed 
upon  the  roots  of  plants, 
decaying  vegetable  matter, 
and  fungi.  They  are  fre- 
quently found  in  the  decay- 
ing wood  and  mold  in  the 
crotch  of  an  old  tree  or  in 
a  stump,  while  several  species  which  feed  on  their  roots  sometimes 
become  abundant  enough  to  do  considerable  damage  to  grasses  and 
grains.  The  adults  are  among  our  largest  flies,  the  common  species 


Fig.  348.     Life  history  of  a  mosquito 
{Cii/ex  sp.).    (Much  enlarged) 

On  the  surface  of  the  water,  a  small  raft  of  eggs 

in  the  water,  several  long,  slender  larvae  (wrigglers) 

and   one  large-headed   pupa   (tumbler)  ;    above 

water,  an  adult.    (From  life,  after  Kellogg) 


the 


FLIES,  MOSQUITOES,  AND  MIDGES 


221 


having  a  wing  expanse  of  from  one  and  one  half  to  two  inches. 
The  giant  crane-fiy    {Holoriisia   mbigmosd),  of  Cahfornia,  is  the 


Fig.  349.    Anopheles  mosquito  and  malaria 

a,  larva;  b,  pupa;  c,  adult;  d,  the  blast  introduced  into  the  blood  by  the  mosquito  ;  e  to  J, 
stages  through  which  the  plasmodium  passes  in  the  red  blood  corpuscle ;  i,  the  spores 
which  enter  new  blood  corpuscles ;  /,  ;«,  the  microgamete ;  a,  0,  the  macrogamete ;  /, 
flagellae  forming ;  ^,  union  of  a  flagellum  with  macrogamete  ;  r,  fusion  of  nuclei ;  s,  the 
vermicule  ;  i  to  y,  formation  of  the  zygote  in  the  mosquito  stomach,  the  fully  developed 
zygote,  J,  rupturing  to  produce  blasts.    (After  J.  B.  Smith) 

largest  species  of  the  order,  being  two  inches  long  and  the  legs 
spreading  some  four  inches.  What  advantage  the  crane-flies  derive 
from  their  size  is  a  question,  as  they  are  very  awkward  and  fragile. 


222 


ELEMENTARY  ENTOMOLOGY 


The  mosquitoes  (Culicidae)  are  so  well  known  as  to  need  no 
description,  but  there  are  many  mosquitolike  flies  which  might 

easily  be  confused  with 
them.  They  have  the 
mouth-parts  developed 
into  a  strong  proboscis 
fitted  for  piercing,  and 
the  antennae  of  the  males 
are  strongly  plumose  (see 
Fig.  53)  ;  but  the  most 
distinctive  character  consists  of  a  fringe  of  scales  along  the  margin 
of  the  wing  and  also  along  the  wing-veins,  which  can  be  readily 
seen  with  a  lens.    The  eggs  are  laid  in  small  masses  on  the  surface 


Fig.  350.    Resting  positions  of  Anopheles  and 
Cnlex  mosquitoes.    (Slightly  enlarged) 

(After  Grassi) 


Fig.  351.    The  yellow-fever  mosquito  {Stegomyia  calopus).    (Enlarged) 
(After  Howard,  United  States  Department  of  Agriculture) 

of  quiet  or  slow-moving  water,  and  hatch  in  from  one  to  four  days. 
The  larvae  are  the  well-known  wrigglers  of  ponds  and  ditches,  with 
their  characteristic  long,  squirming  bodies,  thick  head  end,  and 


FLIES,  MOSQUITOES,  AND  MIDGES 


223 


forked  abdomen.  They  breathe  through  the  respiratory  tube  pro- 
jecting upward  from  the  abdomen,  which  is  thrust  through  the 
surface  of  the  water  as  the  wriggler  rests  at  the  surface.  The 
wrigglers  feed  on  bits  of  organic  matter  and  microorganisms. 
The  pupa  has  the  head  and  thorax  very  remarkably  enlarged,  and 
there  are  two  breathing  tubes  which  project  from  the  back  of  the 


Mil             ^''^v-^fl 

■  k    .             S.  "<J5?^  ^^.        .^^"^Mbi^     ■ 

>■ -^  . 

Hk^   -:>^    ' 

&:^ 

^^^^Ife^^Hii^riflBjfe          ^9  ^^■i^^l^'Sk^K 

IBhB 

Fig. 


35- 


AVing   of   a   mosquito   (Miiuso/na  titillaiis    Walk.)    enlarged,    showing 
scales  on  veins,  and  a  portion  of  same  further  enlarged 

(After  Felt) 


thorax.  The  pupa  stage  lasts  from  one  to  three  days,  the  whole  life 
from  t^g  to  adult  requiring  from  eight  days  to  two  or  three  weeks. 
Not  only  are  mosquitoes  exceedingly  annoying,  rendering  some 
sections  almost  uninhabitable,  but  it  has  been  shown -that  malarial 
fever  is  transmitted  only  by  mosquitoes  of  the  genus  Anopheles, 
and  that  the  dreaded  yellow  fever  is  similarly  carried  only  by  species 
of  the  genus  Stegomyia,  which  has  resulted  in  an  entire  change  in 
the  methods  of  controlling  these   diseases.     Ver)^  much  can  be 


224 


ELEMENTARY  ENTOMOLOGY 


done  toward  the  riddance  of  mosquitoes  in  thickly  settled  com- 
munities by  destroying  their  breeding  places  by  draining  or  filling 
the  pools  and  by  oiling  the  surface  of  small  ponds,  rain  barrels,  etc. 
True  midges  (Chironomidae).  Many  of  these  look  much  like 
mosquitoes,  the  males  having  the  plumose  antennae  and  being  of 
about  the  same  size,  but  the  wing-veins  are  simpler  and  fewer  in 


Fig.  353.    A  midge  [C/i/iv/io»/it.\  sp.).    {(ireatly  enlarged) 
a,  adult  male  ;  /',  pupa  ;  c,  larva,    (.-^fter  Felt) 

number,  and  lack  the  scales.  Most  of  the  larvae  are  aquatic,  being  of 
very  long,  threadlike  worms  which  live  in  the  slime  and  decaying 
vegetation  at  the  bottom  of  pools  and  streams,  where  they  feed  on 
vegetable  matter.  Many  are  a  bright  red  in  color  and  have  been 
called  blood-worms.  The  minute  punkies,  or  "  no-see-ums,"  are 
among  the  worst  enemies  of  the  hunter  and  fisherman,  and  one 
must  have  a  thick  skin  to  withstand  their  bloodthirsty  attacks. 


Fig.  354.   A  punkie,  or  "no-see-um"  (Ceruto/o^ou  £7eii/f  en /i/s).   (Greatly  enlarged) 

a,  adult ;  /',  head  of  same ;  c,  lar\a ;  d,  head  of  same  ;  e,  pupa.    (After  Pratt,  United  States 
Department  of  Agriculture) 


Fig.  355.  (7,  a  net-winged  midge  (Z^^d- 
lioicphala  elcgaiititliis),  female  (two 
and  one  half  times  natural  length);  b,c, 
upper  and  under  sides  of  larva  of  B. 
comstockii  (five  times  natural  length) 

(After  Kellogg) 


225 


226 


ELEMENTARY  ENTOMOLOGY 


They  are  grayish-black,  not  over  one  twenty-fifth  of  an  inch  long, 

and  the  larvae  develop  in  the  water  in  stumps  and  logs  and  under 

damp,  dead  bark. 

The  net-winged  midges  (Blepharoceridae)  are  so  called  on  account 

of  the  peculiar  network  of  small  veins  crossing  the  main  wing- 
veins  around  the  margin  of 
the  wing,  which  are  peculiar  to 
this  family.  The  small,  black 
larvae  live  in  masses  on  the 
rocks  in  swift- running  moun- 
tain streams,  and  seem  to  have 
but  seven  segments  strongly 
constricted  at  each  joint. 

The  Dixa-midges  (Dixidae) 
include  but  a  single  genus, 
whose  larvae  are  also  aquatic. 
Both  of  the  last  families  com- 
prise only  a  few  uncommon 
species,  and  lack  the  whorls 
of  hairs  of  the  male  antennae. 
The  black-flies  (Simuliidae).    Another  pest  of  mountain  lovers  is 

the  black  fly,  the  females  of  which  are  most  bloodthirsty  and  often 


Fig.  356.    A  black  fly  (Simiiliitm  vemisttifii 
(Four  times  natural  size) 

(7,  larva  ;  b^  pupa  ;  ^,  adult.    (After  Weed) 


Fig.  357.    The  fickle  midge  (Sciara  iiiconstaiis),  a  fungus-gnat  sometimes  trouble- 
some in  greenhouses.    (Much  enlarged) 

a,  male  ;  b,  genital  organs  of  same ;  c,  female ;  d,  enlarged  antennal  segments  of  same ; 

e,  maxillary  palpus  of  same  ;  /,  tip  of  abdomen  of  same  from  side  ;  g^  pupa  ;  h,  larva.    (After 

Chittenden,  United  States  Department  of  Agriculture) 


FLIES,  MOSQUITOES,  AND  MIDGES 


227 


appear  in  immense  numbers.  The  larvae  are  found  attached  to 
rocks  in  shallow,  swift-flowing  streams,  where  they  feed  on  various 
minute  plants  and  bits  of  vegetation.  The  adult  flies  are  about  one 
fifth  of  an  inch  long,  stout-bodied,  blackish,  with  short  legs  and  an- 
tennae, though  the  antennae  have  many  distinct  segments.  Recent 
experiments  made  in  the  White  Mountains  indicate  that  it  may  be 
possible  to  eradicate  the  larvae  in  mountain  resort  regions  by  oiling 
the  streams  with  Phinotas  oil.  The  southern  buffalo  gnat  is  a 
serious  pest  of  domestic  animals  in  the  South,  such  immense 
swarms  sometimes  appearing  as  to  cause  their  death. 


Fig.  358.    The  pine-cone  willow  gall  caused  by  a  cecidomyiid,  cut  open  at 
right  to  show  maggots  within 

(After  Washburn) 

Fungus-gnats.  Wherever  there  is  decaying  vegetable  matter 
or  damp  fungi,  as  in  decaying  wood,  under  damp  bark,  in  decom- 
posing leaves,  etc.,  there  are  found  small,  white  or  pink  maggots, 
which  develop  into  the  graceful  little  fungus-gnats  {Mycetophilidac). 
The  larvae  often  stick  together  in  large  patches,  and  sometimes 
form  long  processions  of  wriggling  maggots.  One  species  feeds  on 
injured  apples,  while  another  has  been  shown  to  cause  a  form  of 
potato  scab,  and  one  is  a  serious  pest  of  mushrooms,  but  most  of  the 
larvae  are  entirely  harmless.  The  flies  are  mosquitolike  in  general 
form,  but  the  antennae  are  bare  and  the  coxae  are  unusually  long. 


228 


ELEMENTARY  ENTOMOLOGY 


Fig.  359.     Pear  midge   [Di- 
plosh  pyrivora).     (Enlarged) 

(After  Riley) 


Gall-gnats.  The  smallest  and  most  deli- 
cate of  the  gnatlike  flies  are  the  gall-gnats 
{Cecidomyiidae).  The  adults  are  rarely 
over  one  eighth  of  an  inch  long,  with  long 
antennae  clothed  with  short  hairs,  and  with 
the  wing-veins  greatly  reduced  in  number. 
They  will  be  rarely  noticed  by  the  begin- 
ner, but  the  work  of  the  larv^  is  often 
much  in  evidence,  owing  to  their  feeding 
within  the  stems  and  leaves  of  plants  and 
giving  rise  to  galls.  Frequently  a  green, 
cone-shaped  gall  is  found  on  the  tips  of 
willow  twigs,  known  as  the  pine-cone 
willow-gall,  which  is  caused  by  one  of 
these  larvae  {Cccidomyia  strobiloides). 
The  larvae  of  the  clover-seed  midge  live  in 
the  heads  of  clover  and  destroy  the  seed 
so  that  in  many  sections  it  is  often  impossible  to  mature  it.  The 
best-known  exam- 
ple of  the  family, 
an  d  our  worst  wheat 
pest,  is  the  Hessian 
fly,  so  called  be- 
cause it  was  sup- 
posedly introduced 
in  straw  brought 
over  to  Long  Is- 
land by  the  Hes- 
sian troops  during 
the  Revolutionary 
War.  The  mag- 
gots bore  into  the 
crown  and  stalks 
of  wheat,  weaken- 
ing the  plant  and 
seriously  curtailing 
production  where 
they  are  abundant. 


Fig.  360.   The  Hessian  fly,  adult  male.   (Much  enlarged) 
(After  Marlatt,  United  States  Department  of  Agriculture) 


FLIES,  MOSQUITOES,  AND  MIDGES 


229 


Fig.  361.    Horse-fly  {Tahanus  atratics) 
n,  lan'a  ;  fi,  pupa  ;  c,  adult,    (.\fter  Riley) 


SHORf-HORNEl)    FLIES   {BRACHYCEKA) 

In  this  section  the  antennae  are  composed  of  from  three  to  five 
segments,  the  famihes  being  divided  into  three  groups  according 

to  the  structure  of  the 
\      V/       /  antennae,  and  being  fur- 

ther   distinguished    by 
w^^      ^^-"•••""?=grr^^^)^.^=r:^^^grr^^^^  the  wing-vcnation. 

.3     X.       ,     — ..-^jMBirfiii*  .       .   .  ^   ev         In  the  first  group  the 

third  segment  of  the  an- 
tenna is  clearly  ringed, 
showing  that  it  is  made 
up  of  several  segments 
grown  together. 

Horse-flies.  The  best- 
known  family  of  this 
group  is  that  of  the 
horse-flies  {Tabaiiidae). 
They  are  well-known 
pests  of  live  stock  and  often  become  annoying  to  man.  The  adults 
have  short,  broad  heads,  large  eyes,  thick  bodies,  short,  oval  abdo- 
mens, and  strong,  powerful  wings,  which  enable  them  to  outstrip  the 
swiftest  horse.  They 
are  often  most  trouble- 
some along  wooded 
roads,  where  they  will 
attack  a  horse  in 
swarms  and,  with  their 
loud  buzzing,  render 
the  animal  frantic. 
The  larvae  are  long, 
pointed  maggots  which 
live  mostly  in  water  in 
swampy  places  and 
along  the  edges  of 
streams  and  ponds, 
and  are  carnivorous.  In  the  swamp  lands  of  southern  Texas  and 
Louisiana  the  large  horse-flies  appear  in  such  swarms  as  to  make 
life  for  cattle  almost  impossible,  and  along  our  coasts  wherever 


Fig.  362.     A   "green-head"  {Tabanus  liiieohx  Fab.) 
(Much  enlarged) 

(After  Lugger) 


2^^0 


ELEMENTARY  ENTOMOLOGY 


there  is  marshland  the  well-known  green  heads  annoy  bathers  as 
well  as  animals.  Our  largest  horse-fly  is  an  inch  long,  with  a 
two-inch  wing  expanse,  and  of  a  dull  black  color,  while  other 
common,  smaller  species  are  brown,  with  the  wings  banded  with 
black.  Only  the  females  are  bloodsuckers,  the  males  feeding  on 
the  pollen  of  flowers. 

The  soldier-flies  (Stratiomyidae)  somewhat  resemble  the  smaller 
horse-flies,  and  are  so  named  on  account  of  the  bright  yellow  or  green 
stripes  across  the  abdomen.    The  antennae  are  somewhat  longer 


Fig.  363.    Stratiomyia  discalis.    (Greatly  enlarged) 
(After  Lugger) 

and  the  wing  venation  is  quite  characteristic.  The  adults  are  found 
on  flowers  near  water,  and  the  larvae  are  carnivorous  or  feed  on 
decaying  vegetable  matter,  living  in  water,  earth,  or  decaying  wood. 

In  the  second  group  are  found  two  families  having  four  or  five 
distinct  antennal  segments,  —  the  robber-flies  {Asilidac)  and  the 
nearly  related  Midas-flies  {Midaidac),  which  have  very  similar 
habits. 

The  robber-flies  (Asilidae).  They  are  well  named,  being  large, 
hairy,  ferocious-looking  flies,  which  are  strong,  swift  flyers.  They 
may  often  be  seen  resting  quietly  on  a  dead  twig,  which  they  closely 
resemble  in  color ;  suddenly  they  will  dart  off  and  in  mid-air  will 
snatch  a  fly  or  any  insect  which  they  can  overpower,  in  much  the 


FLIES,  MOSQUITOES,  AND  MIDGES 


2^1 


Fig.  364.    A  robber-fly  [Stenopogon  inqninattis),  and 

another   {Dasylis  soceata)    resembling   a   bumble-bee. 

(Natural  size) 

(After  Kellogg) 


same  manner  as  does  a  dragon-fly.  The  most  common  species  are 
of  a  sober  gray  color,  marked  with  white,  yellow,  or  black,  with  a 
long,  tapering  abdomen,  long,  narrow  wings,  large,  keen  eyes,  and 
a  strong  proboscis,  with  which  they  suck  the  juices  of  their  prey. 

Other  species  are 
thickly  clothed 
with  black  and 
yellow  hairs,  so 
that  they  closely 
resemble  bumble- 
bees. The  lar\'se 
are  mostly  pre- 
dacious and  live 
in  the  ground  or 
in  decaying  wood, 
where  they  feed 
on  the  larvae  of 
beetles    and    on 

decaying  vegetable  matter.  The  robber-flies  can  hardly  be  con- 
sidered beneficial,  as  they  rarely  feed  on  noxious  insects  to  any 
extent,  and  often  destroy  bees. 

In  the  third  group  is  a  considerable  series  of  important  families, 
in  which  the  first  two  segments  of  the  antennae  are  small  and  the 
third  is  large  and  clublike  and  bears  a  single, 
conspicuous  bristle,  called  an  arista. 

The  bee-flies  {Bomhyliidae)  are  medium-sized, 
oval-shaped  flies,  with  a  thick  covering  of 
yellow  hairs,  giving  them  a  resemblance  to 
bees  which  is  increased  by  their  habit  of  hover- 
ing over  flowers,  upon  the  nectar  of  which  the 
flies  feed  by  means  of  their  long  tongues. 
Some  of  them  frequent  orchards  and  aid  in 
carrying  the  pollen  from  flower  to  flower  by 
means  of  the  body  hairs,  to  which  it  adheres. 
The  lar\^ae  live  in  the  ground  and  are  very  beneficial,  being  para- 
sitic upon  cutworms,  army- worms,  and  grasshopper  eggs. 

The  long-legged  flies  (Dolichopodidae)  should  be  mentioned,  for 
they  are  of  such  a  striking  metallic  green,  or  blue,  as  to  attract 


Fig.    365.     A    bee-fly 
{Bombylius  sp.).    (En- 
larged) 

(After  Weed) 


232 


ELEMENTARY  ENTOMOLOGY 


attention  as  they  flit  over  rank-growing  foliage  in  damp  places.  The 
adults  feed  on  small  flies,  and  the  larvae  live  underground,  being 

either  predacious  or  feeding  on 
decaying  vegetable  matter. 

The  wasp-flies  {Conopidae) 
should  also  be  mentioned,  on 
account  of  their  close  rell%ai- 
blance  to  wasps,  with  ^wich 
they  may  readily  b^confused  at 
first  glance,  and  which  they 
undoubtedly  mimic.  They  are 
narrow-waisted,  the  tip  of  the 
abdomen  is  like  that  of  a  wasp, 
and  they  are  often  banded  and 
colored  to  heighten  the  likeness. 
The  head  is  robust,  which  has 
given  them  the  common  name 
of  "  thick-headed  flies."  The 
bodies  of 


Fig.  366. 


A   long-legged 
ditiiis  sipho) 

(After  Lugger) 


fly    [Psilopo- 


larvae    are    parasitic    within    the 

wasps,   bumble-bees,  and  grasshoppers,   on 

which  the  eggs  are  laid.   The  adults  feed  on 

nectar  and  pollen  of  flowers,  over  which  they 

may  be  found  hovering. 

The  flower-flies  (Syrphidae)  are  medium- 
to-large-sized,  bright-colored  flies  which  feed 

upon  nectar  and  pollen  of  flowers,  over 
which  they  may  be  seen 
to  hover,  almost  motion- 
less, for  several  seconds 
and  then  to  dart  off  and 
as  quickly  return.  These 

flies  may  be  readily  recognized  by  a  thicken- 
ing which  looks  like  a  vein  extending  across 
the  middle  of  the  wing.  Our  more  common 
species  of  the  genus  Syrp/uis  have  the  abdo- 
men marked  with  alternate  bands  of  black  and 
yellow,  and  have  greenish,  bronze,  or  yellowish 
bodies.    They  lay  their  small,  oval,  white  eggs 


Fig.    367.      A    wasplike 

fly  [P/iysocephala  njfitiis). 

(One  and  one  half  times 

natural  size) 

(After  Kellogg) 


Fig.    368.     The    bee- 
fly     [Eristaiis     ienax). 
(Natural  size) 


FLIES,  MOSQUITOES,  AND  MIDGES 


233 


Fig.  369.     Rat-tailed    maggot,    larva    of 
a  syrphid  fly  similar  to  Fig.  368.    (Twice 
natural  size) 

(After  Kellogg) 


among  colonies  of  plant-lice,  around  which  the  flies  may  be  seen 
hovering,  and  the  maggots  devour  the  aphides  greedily,  being 
among  their  most  important  natural  enemies.  Some  of  the  larger 
species  are  thickly  covered  with  yellow  and  black  hairs,  thus  closely 
resembling  bumble-bees,  in  whose  nests  their  larvae   reside.     A 

common  species  which  is 
often  found  on  windows  in 
fall  is  known  as  the  drone-fly, 
from  its  close  resemblance 
to  a  honey-bee  drone.  Its  lar- 
xa.  lives  in  foul  water  and 
excrement,  and  is  typical  of 
a  group  which  is  often  found 
in  privies  and  similar  filth. 
The  larva  is  maggotlike  in 
shape  but  has  a  long,  extensile  tube,  through  which  it  breathes, 
projecting  from  the  tip  of  the  abdomen  to  the  surface  of  the  food- 
material,  which  has  given  it  the  name  of  "  rat-tailed  maggot." 
None  of  the  family  seems  to  be  injurious,  and  those  larvae  which 
feed  on  plant-lice  are  exceed- 
ingly beneficial. 

Bot-flies  (Oestridae) .  Another 
family  in  which  the  flies  are  well 
covered  with  hairs,  so  as  to 
closely  resemble  bees,  is  that  of 
the  bot-flies,  whose  maggots  are 
among  the  worst  insect  parasites 
of  domestic  animals.  The  adults 
have  very  rudimentary  mouth- 
parts,  so  that  they  probably  take 
no  food.  The  eggs  are  usually 
laid  on  the  hair  of  various  animals,  from  which  they  are  licked  off 
and  pass  into  the  alimentary  tract,  though  others  lay  them  upon 
the  lips  or  in  the  nostrils  of  the  host.  Among  the  more  common 
are  the  horse  bot-fly,  which  gives  rise  to  the  bots  in  the  stomach 
of  the  horse,  the  ox-warble  fly,  whose  maggots  pass  from  the 
stomach  through  the  tissues  of  cattle  and  finally  emerge  through 
holes  in  the  skin,  causing  "  grubby  "  hides,  and  the  sheep  bot-fly, 


Fig.  370.  A  syrphus-fly  ( ]'olucena  erecta) 
which  resembles  a  bumble-bee  and  is  an 
inquiline  in  bumble-bees'  nests  (after 
S.  J.  Hunter);  and  a  typical  syrphus-fly 
{^Syn-phits  ribesii) 


2  34 


ELEMENTARY  ENTOMOLOGY 


whose  maggots  work  in  the  nasal  sinuses  of  sheep,  causing  "  grub- 
in-the-head, "  which  often  results  in  fatal  vertigo,  or  "staggers." 

Other  species  affect  various  wild 
mammals,  one  inhabiting  rabbits 
being  particularly  common  in  the 
South.  When  full  grown,  the  bots 
pass  out  with  the  excreta,  or  drop 
to  the  ground,  in  which  they 
pupate. 

The  muscids.  The  last  group 
of  the  typical  flies  is  much  the 
largest  and  is  now  held  by  most 
students  of  this  order  to  represent 
from  twenty  to  thirty  families,  so 
that  it  may  be  considered  as  a 
superfamily.  They  are  all  com- 
monly called  muscids  (superfamily 
Muscina)  and  the  house-fly  is  the 
best-known  example.  No  attempt 
will  be  made  to  give  the  technical 
distinctions  by  which  the  different  families  or  subfamilies  may  be 
distinguished,  for  the  knowledge  of  an  expert  is  required  for  their 
recognition  ;  but  the  different  groups  will  be  considered  according 


Fig. 371. 


The  ox  bot-fly  {Hypoden 
liiieata) 


(After  Marlatt,  United  States  Department 
of  Agriculture) 


Fig.  372.    The  horse  bot-fly  [Gastrophiliis  eqiti),  male  ;  abdomen  of  female  at  left; 
egg  attached  to  hair  at  right.    (Much  enlarged)         ^ 

(After  Lugger) 


FLIES,  MOSQUITOES,  AND  MIDGES 


235 


Fig.  373.    Bots  in  stomach  of  a  horse  ;  some  removed  to  show  point  of  attachment 
(After  Osbom,  United  States  Department  of  Agriculture) 


to  their  habits.  All  are  alike  in  having  three-segmented  antennae 
bearing  a  strong  bristle  near  the  base,  the  modifications  of  which  aid 
in  distinguishing  the  groups.  The  larvas  are  typical  white  or  light- 
colored  maggots 
livingwithin  their 
food,  and  the  pu- 
paria  are  usually 
formed  on  or  in 
the  soil. 

The  discovery 
in  recent  years 
that  the  common 
house-fly  and  also 
many  of  its  near 
relatives  are  re- 
sponsible for  the 
spread  of  typhoid 
fever,  intestinal 
diseases  of  in- 
fants, and  possibly  other  infectious  diseases  has  given  new  interest 
to   the  study  of  the   common   flies   heretofore   considered   mere 


Fig.  374.    Stable-fiy  {Sto/No.xys  calcit7-aiis),  adult,  larva,  and 
puparium.    (Enlarged) 

(.\fter  Howard,  United  States  Department  of  Agriculture) 


236  ELEMENTARY  ENTOMOLOGY 

nuisances.  Very  similar  and  almost  indistinguishable  from  the 
house-fly  is  the  common  stable-fly,  so  annoying  to  cattle.  The  mouth- 
parts  of  the  females  are  fitted  for  piercing.  Just  before  a  storm 
these  flies  frequently  come  into  houses  and  annoy  us,  from  which 
comes  the  saying  that  flies  bite  before  a  storm.  Like  those  of  the 
housefly,  the  larvae  live  in  fresh  horse  manure.  The  little  horn-flies 
often  annoy  cattle  by  assembling  on  their  flanks  and  clustering  at 
the  base  of  the  horns.    The  maggots  develop  in  cow  manure. 

The  flesh-flies  (Sarcophagidae)  are  so  called  because  many  of  them 
lay  their  eggs  on  the  bodies  of  dead  animals  or  in  open  wounds. 


Fig.  375.    The  horn-fly.    (Enlarged) 
(7,  egg  ;  1^,  fly  ;  c  and  d,  head  and  mouth-parts.    (After  J.  B.  Smith) 

though  some  of  the  larvse  live  in  dung  and  decaying  vegetable 
matter.  The  common  flesh-fly  {Sarcophaga  sarraccnia)  looks  like 
a  very  large  house-fly  and  gives  birth  to  live  maggots  (the  eggs 
hatching  in  the  body  of  the  female),  which  are  deposited  on  fresh 
meat  or  in  open  wounds.  The  blow-flies  and  blue-bottle  flies  are 
about  the  size  of  house-flies,  with  the  abdomen  steely-blue  or  green- 
ish, and  lay  their  eggs  on  meat,  cheese,  or  other  provisions,  which 
are  said  to  be  "  blown."  The  eggs  hatch  in  a  day  ;  the  maggots  feed 
on  the  juices  of  decaying  meat  and  become  full  grown  in  a  few 
days.  The  common  blue-bottle  or  green-bottle  fly  {Liicilia  cacsar) 
also  lays  its  eggs  on  cow  dung.  The  screw-worm  fly  {CJirysoniyia 
macellaria)  is  a  bright,  metallic  green,  about  one  third  of  an  inch 


FLIES,  MOSQUITOES,  AND  MIDGES 


long,  with  four  black  stripes  on  the  thorax.  It  is  one  of  the  most 
serious  pests  of  cattle  in  the  South  and  West,  laying  its  eggs  in 
wounds  or  sores  in  which  the  maggots  develop,  causing  very  serious 
festering  sores.  Sometimes  it  oviposits  in  human  nostrils,  the 
work  of  the  larvae  not  infrequently  resulting  fatally. 


Fig.  376.    The  screw-worm  fly  {Liccilia  inacellaria) 
(7,  b,  c,  larva  and  details  of  same  ;  d,  pupa  ;  f,  adult ;  /,  head  from  side.    (After  J.  B.  Smith) 

The  tachina-flies  (Tachinidae)  are  found  frequenting  flowers  ;  they 
somewhat  resemble  the  last  group,  but  are  commonly  recognized 
by  the  numerous  stout  bristles  and  hairs  with  which  they  are  clothed. 
The  adults  are  mostly  of  a  modest  gray  color,  with  thorax  streaked 
with  blackish-brown  or  gray,  though  some  have  yellow-banded  or 
red  abdomens.  The  eggs  are 
laid  on  the  bodies  of  caterpillars 
or  on  foliage  on  which  they  are 
feeding,  and  the  maggots  are 
parasitic  within  them.  Any  one 
who  has  tried  rearing  moths 
from  their  caterpillars  will  have 
encountered  these  flies,  for  often 
a  score  or  more  will  inhabit  a 
large    caterpillar.      When    full 

grown  the  puparia  are  formed  within  the  caterpillar  or  pupa,  which 
never  transforms.  Some  European  species  w^hich  are  parasitic  on 
the  gypsy  moth  have  been  imported  into  Massachusetts  with  the 
hope  that  they  may  aid  in  controlling  that  pest  in  this  country. 


Fig.  377.    A  parasitic  tachina-fly 
and  its  puparium 

(After  Weed) 


2  38 


ELEMENTARY  ENTOMOLOGY 


The  tachina-flies  are  among  our  most  beneficial  insects,  their  white 
eggs  being  commonly   found   on   the   necks   of  caterpillars    and 

grasshoppers,  the  flies 
appearing  in  large  num- 
bers whenever  there  is 
an  outbreak  of  such 
caterpillars  as  the  army- 
worm. 

Root-maggot  flies 
(Anthomyiidae)  are  an- 
other group  of  trouble- 
some flies  belonging  to 
this  series,  many  of  whose 
larvae  are  serious  pests 
of  the  roots  of  vegeta- 
bles. The  flies  somewhat 
resemble  house-flies,  but 
are  smaller  and  slighter 
in  build.  The  cabbage- 
maggot  and  onion-maggot  are  well-known  examples  of  these  inju- 
rious larvae,  and  wherever  small  flies  are  seen  hovering  around 
these  or  other  root  crops,  such  as  radishes,  turnips,  beets,  etc., 


Fig.  378.    The  cabbage-maggot.    (Enlarged) 

a,  larva  ;  /',  pupa  ;  c,  adult ;  d,  head  ;  c,  antenna. 
(After  Riley) 


Fig.  379.    The  apple-maggot 

a,  adult ;   b,  larva,  or  maggot ;   c,  funnel  of  spiracle  on  head  ;  </,  puparium  ;  c,  portion  of 

apple  showing  injury  by  maggots,  {a,  b,  d,  enlarged;  c,  reduced.)    (After  Quaintance,  United 

States  Department  of  Agriculture) 


FLIES,  MOSQUrrOKS,  AND  MIDGES 


239 


they  may  well  be  regarded  with  suspicion.  One  species  occasionally 
attacks  the  roots  of  corn,  and  another,  the  beet  leaf-miner,  makes 
tortuous  mines  in  beet  leaves. 

The  fruit-flies  (Trypetidae)  burrow  in  the  flesh  of  fruits  and  in 
the  stems  of  plants.  The  common  round  gall  on  the  golden-rod  is 
caused  by  the  maggot  of  one  of  this  group,  most  of  which  are 
medium-sized  flies,  often  metallic  in  color  and  usually  with  strik- 
ingly banded  or  mottled  wings.  In  New  England  the  common 
apple-maggot  {RJiagolctis  fovioncUa),  or  "railroad  worm,"  which 


Fk;.  3S0.    A  pomace-fly  [Dro.sophila  ainpelophila).    (Enlarged) 

(7,  adult ;   b,  antenna  of  same  ;   c^  base  of  tibia  and  first  tarsal  segment ;   d,  c,  puparium 

from  side  and  above  ;  /,  larva ;  g,  anal  spiracles  of  same.    (After  Howard,  United  States 

Department  of  Agriculture) 

bores  through  the  flesh  of  the  apples,  is  a  well-known  example,  the 
adult  being  black  and  white  with  black-banded  wings.  In  Mexico 
a  similar  species  infests  the  orange  and  is  occasionally  imported 
into  this  country.  The  little  pomace-flies  {Drosophila  sp.),  small, 
yellowish  flies  about  one  eighth  of  an  inch  long,  are  common  about 
cider  mills  and  wherever  there  is  decaying  fruit,  in  which  their 
maggots  develop. 

II.    PUPIPARA 

This  suborder  includes  three  parasitic  families,  with  but  few 
species,  so  named  on  account  of  the  peculiar  mode  of  reproduction. 
The  eggs  and  larvae  are  developed  within  the  body  of  the  female 
and  are  given  birth  when  mature  and  all  ready  to  pupate. 


240 


ELEMENTARY  ENTOMOLOGY 


Some  of  the  louse-flies  {Hippoboscidac)  are  winged,  though  some 
of  them  cast  off  or  bite  off  their  wings,  and  are  frequently  found 
on  birds  of  prey,  while  others  are  common  on  various  birds  and 

mammals.  The  bodies  are 
very  much  flattened,  the 
head  is  joined  to  the  thorax 
broadly,  the  antennae  con- 
sist of  a  single  segment, 
and  the  wing-venation  is 
very  simple.  The  best- 
known  example  of  the 
wingless  forms  is  the  com- 
mon sheep-tick  {Mclopha- 
gus  ovimis),  which  should 
be  carefully  distinguished  from  the  true  ticks 
(belonging  to  the  Arachnida),  and  which  is  the 
only  troublesome  member  of  the  family. 

A  nearly  related  family  {Nycteribiidae),  look- 
ing like  small  spiders,  are  known  as  bat-ticks 
and  are  even  more  degenerate  in  structure.  The 
third  family  {Braulidac)  consists  of  a  single  spe- 
cies, the  bee-louse,  a  minute  insect  about  one  six- 
teenth of  an  inch  long,  which  is  found  clinging 

to  the  thorax  of  queen  and  drone  bees 


Fig.  381.   A  louse-fly  (Olfersia  sp.).   (Enlarged) 


Fig.  382.  Sheep-tick 
{Melophagus  ovinus) 


Fleas  (Siphonaptera) 

The  fleas  may  be  considered  in  con- 
nection with  the  flies,  for  they  were 
formerly  thought  to  be  wingless  Dip- 
tera,  but  are  now  classed  as  a  distinct 
order.  The  name  of  the  order  is  de- 
rived from  two  Greek  words,  sipJwn  (a 
tube)  and  aptcros  (wingless),  referring 
to  the  tubelike  mouth-parts  and  the 
lack  of  wings.  The  fleas  have  an  oval 
body  which  is  very  strongly  compressed  laterally,  enabling  them  to 
pass  through  narrow  cracks.  They  are  usually  of  a  brown  color, 
with  small  heads  bearing  sucking  or  piercing  mouth-parts,   and 


Fig.  383.    Bee-louse  [Braula 
caeca)  and  its  larva.    (Greatly- 
enlarged) 


FLIES,  MOSQUITOES,  AND  MIDGES 


241 


have  the  merest  rudiments  of  wing-pads.  The  posterior  legs  are 
strongly  developed,  so  that  the}-  are  able  to  jump  a  considerable 
distance.  In  the  adult  stage  they  live  upon  various  warm-blooded 
animals,  sucking  their  blood.  The  eggs  are  scattered  about  in  the 
sleeping  places  of  domestic  animals  and  in  the  cracks  of  floors. 
The  larvae  are  wormlike  creatures,  with  a  distinct  head,  but  without 
legs.  They  ha\'e  biting  mouth-parts,  and  feed  upon  particles  of 
decaying  animal  and  vegetable  matter  always  abundant  in  the 
places  in  which  they  live.  The  full-grown  larva  spins  a  cocoon  in 
which  the  pupal  stage  is  passed.  In  view  of  these  habits,  in  addition 
to  cleansing  domestic  animals  it  is  also  necessary  to  thoroughly 
clean  the  sleeping  places  of  cats  and  dogs,  to  scrub  the  floors, 
and  to  treat  large  cracks,  in  which  rubbish  may  accumulate,  with 
gasoline,  kerosene,  or  a  similar  contact  insecticide.  In  temperate 
climates  the  common  species  which  lives  upon  dogs  and  cats  is 
the  only  one  often  troublesome  to  human  beings  ;  in  the  tropics 
fleas  are  much  more  abundant,  and  attack  man  as  well  as  the 
domestic  animals. 


Fig.  384.    Cat  and  dog  flea  {Ctenocephalus  canis).    (Much  enlarged) 

a,  egg ;   b,  lan-a  in  cocoon  ;   c,  pupa ;   d,  adult ;   c,  mouth-parts  from  side ;  /,  antenna ;  g, 
labium  from  below.    (After  Howard,  United  States  Department  of  Agriculture) 


242  ELEMENTARY  ENTOMOLOGY 

Summary  of  the  Diptera 

Suborder  I.  Typical  'D\-piQra.{Dipte)-(i  ge/iuina). 

Section    i.  Antennae  with  over  five   segments.    Long-horned   Diptera 
(^Neinatoceni). 
Aquatic  larvae. 

Families.    Mosquitoes  {Citlicidae). 

Midges  {CJiiroiioviidae^  etc.). 
Black-flies  (Simuliidae). 
Nonaquatic  larvae. 

Families.    Crane-flies  {Tipulidae). 

Fungus-gnats  {Mycefop/iilidae). 
Gall-gnats  {Cecidotnyiidae). 
Section  2.  Antennae  with  five  or  less  segments.    Short-horned  Diptera 
{Brachycerd). 
Third  antennal  segment  ringed. 
Families.    Horse-flies  (Tabamdae). 

Soldier-flies  iStratioinyidae). 
Antennae  with  four  or  five  segments. 
Families.    Robber-flies  {Asilidae). 
Midas-flies  (JMidaidae). 
Antennae  with  three  segments  ;  with  an  arista  on  third  segment. 
Families.    Bee-flies  {Boiiibyliidae). 
Flower-flies  {Syrphidae). 
Wasp-flies  [Coiiopidac). 
Bot-flies  {Oestridae). 
Superfamily.    Muscids  {Muscina). 

House-flies,  etc.  {Musctdae). 
Flesh-flies  {Sarcophagidae). 
Root-maggot  flies  i^Anthoniyiidae). 
Tachina-flies  ( TacJiinidae). 
Fruit-flies  ( Trypetidae). 
Suborder  H.   Pupipara. 

Families.    Louse-flies  {Hippobosctdae). 
Bat-ticks  {Nycteribiidae). 
Bee-lice  {Bniulidae). 


CHAPTER  XV 

THE  SAW-FLIES,   ICHNEUMONS,  WASPS,   BEES,   AND  ANTS 
(HYMENOPTERA) 

Characteristics.  Insects  with  four  membranous  wings,  with  few  cross-veins, 
the  hind-wings  smaller  than  the  fore-wings  ;  mouth-parts,  formed  for  both  biting 
and  sucking,  or  lapping ;  abdomen  of  the  females,  usually  bearing  an  ovipositor 
or  sting ;  metamorphosis,  complete. 

The  insects  of  this  order  are  mostly  beneficial,  though  a  few 
families  are  injurious  to  crops.  Probably  no  other  invertebrate  ani- 
mals, and  very  few  vertebrates,  have  as  highly  developed  instincts 
as  many  of  the  insects  of  this  order,  the  social  ants,  bees,  and 
wasps  having  always  been  the  objects  of  the  greatest  popular  and 
biological  interest  on  account  of  their  high  intelligence,  if  it  may 
be  so  termed. 

The  wings  are  membranous,  with  but  few  veins,  are  frequently 
clothed  with  short  hairs,  and  are  held  together  by  a  row  of  hooks 
on  the  anterior  margin  of  the  hind-wings,  which  grasp  a  fold  of 
the  hind-margin  of  the  fore-wings,  so  that  the  two  wings  move  to- 
gether as  one.  The  name  of  the  order  is  derived  from  Jiymen  (a 
membrane)  and  pteron  (a  wing).  The  mandibles  are  always  well 
developed  and  used  for  biting.  In  the  ants,  bees,  and  wasps  the 
maxillae  are  more  or  less  developed  as  a  sheath  surrounding  the 
labium,  which  is  prolonged  into  a  tongue,  so  that  these  mouth- 
parts  are  adapted  for  sucking  or  lapping  the  liquid  food. 

Most  of  the  larvae  are  footless  and  maggotlike,  living  within  the 
food,  where  the  eggs  are  placed  by  the  adults,  but  the  larvae  of  the 
first  two  families  bear  both  true  legs  and  several  pairs  of  abdominal 
prolegs,  and  resemble  caterpillars  in  both  form  and  habits.  Many 
species  spin  a  cocoon  before  pupating,  and  the  newly  formed  pupae 
are  white,  with  the  legs,  wings,  and  antennae  pressed  close  to  the 
body. 

The  different  families  fall  into  several  natural  groups  recogniz- 
able by  their  structure  and  habits. 

243 


244 


ELEMENTARY  ENTOMOLOGY 


Suborder  I.    The  Boring  Hvmenoptera  {Terebrantia) 

In  the  first  suborder  the  females  bear  a  well-developed  ovipositor, 
with  which  the  eggs  are  inserted  into  the  food  plant  or  host  insect, 
and  the  trochanters  of  the  hind-legs  consist  of  two  segments. 

1.    PLANT-EATING    HVMENOPTERA 

The  first  two  families  are  distinguishable  by  the  base  of  the  ab- 
domen being  broadly  joined  to  the  thorax,  with  no  constriction  at 
this  point. 

The  saw-flies  {Tenthredinidae)  are  so  called  on  account  of  the  saw- 
like ovipositor.  It  is  toothed  at  the  tip,  having  a  structure  which 
enables  the  females  to  insert  their  eggs  beneath  the  surface  of  leaves 


5 


The  American  rose-slug  { Kit  de  Ion  via  rosae) 


«,  adult  saw-fly  ;  b^  mature  larva ;  r,  work  of  larva  on  rose  leaf  ;  </,  piece  of  rose  leaf  showing 
location  of  egg  near  margin  ;  e,  egg.  (a,  b,  c,  and  e  enlarged,  d,  natural  size.)    (After  Chitten- 
den, United  States  Department  of  Agriculture) 

or  in  the  stems  of  plants.  They  are  medium-sized  insects  from  one 
fourth  to  one  half  of  an  inch  long,  usually  blackish  or  yellow-and- 
black  in  color,  with  the  wings  folded  over  the  back  when  at  rest. 
The  larvae  resemble  small  caterpillars,  but  usually  have  a  larger 


HYMENOPTERA 


245 


number  of  prolegs  on  the  abdomen,  and  lack  the  hard  shield  usually 

found  on  the  prothorax 
of  lepidopterous  cater- 
pillars. Most  of  them 
feed  on  foliage,  and  many- 
are  quite  injurious.  Sev- 
eral species  are  soft- 
bodied  and  covered  with 
a  viscid,  slimy  matter, 
which  has  given  them 
the  name  of  "slugs." 
Among  the  more  com- 
mon species  are  the 
yellow-and-green  currant 
worms  {Nematus  ribc- 
sii),  which  devour  the 
foliage  of  currants  and 
gooseberries,  the  rose- 
slug  {Monostcgia  rosac), 
which  strips  off  the  sur- 
face of  rose  leaves,  leaving  them  brown  as  if  scorched,  and  the 

pear-slug  {Eiiocampa  cc- 

rasi),  which  injures  pear 

and  cherry  foliage  in  the 

same  manner.  Other  spe- 
cies often  defoliate  straw- 
berry and  raspberry  bushes, 

and  there  are  numerous 

species    which    may    be 

found   on    various    shade 

and  forest  trees,   one   of 

the  most  injurious  being 

the     larch     saw-fly     {Ly- 

gaeoncmatjts    crichsonii) , 

which  has  defoliated  and 

thus  destroyed  large  areas 

of  larch  in  New  England 

and  Canada. 


Fig.  3S6.    The  pear-slug 

a,  adult  saw-fly,  female ;   /',  lan^a  with  slime  removed  ; 

c,  same  in  normal  state  ;  d,  leaves  with  larva  (natural 

size),    {a,  b,  c,  much  enlarged.)     (After  Marlatt,  United 

States  Department  of  Agriculture) 


Fig.  387.    Pear-slug,  illustrating  method  of  ovi- 
position  and  emergence  of  larva.    (Enlarged) 

<7,  cutting  of  cell  beneath  epidermis  of  leaf,  showing 
the  tip  of  the  ovipositor  ;  i,  the  cell  after  the  egg 
has  been  deposited  ;  c,  same  after  the  escape  of  the 
larva.  (After  Marlatt,  United  States  Department  of 
.Agriculture) 


246 


ELEMENTARY  ENTOMOLOGY 


Horn- tails  {Siricidae).  The  ovipositor  of  the  horn-tails  is  cylin- 
drical, more  like  a  borer,  and,  as  it  projects  from  the  abdomen,  has 
given  the  family  its  name.  The  eggs  are  laid  within  the  stems  of 
grasses  and  various  plants,  such  as  berry  canes  and  alder,  while 
some  of  the  larger  species  deposit  them  in  the  solid  wood  of  various 
shade  and  forest  trees,  usually  when  the  tree  is  beginning  to  die. 


Fig.  388.    The  pigeon  tremex,  or  horn-tail  ( Tremex  columba) 

a,  larva  with  young  larva  of  Thalessa  fastened  to  its  side  ;  b^  its  head  ;  c,  d,  female  and  male 
pupae  ;  r,  female.    (After  Riley) 

The  larvae  feed  within  these  plants,  tunneling  out  burrows,  and 
are  difficult  to  combat.  Fortunately  but  few  are  of  considerable 
economic  importance. 


2.    GALL-INHABITING  HYMENOPTERA 

Gall-flies  (Cynipidae).  The  gall-flies  lay  their  eggs  in  the  leaves 
and  stems  of  plants,  and  the  injury  done  by  the  developing  larvae 
causes  the  formation  of  a  characteristic  gall  by  the  plant  tissues 
surrounding  them.    The  adults  are  small  insects  resembling  wasps, 


HYMENOPTERA 


!47 


and  the  abdomen  is  joined  to  tiie  thorax  by  a  slender  petiole,  or 

stalk,  as  in  the  fam- 
ilies named  below, 
from  which  they 
are  distinguished  by 
lacking  the  dark 
spot,  or  stigma, 
toward  the  end  of 
the  anterior  margin 
of  the  fore-wings. 
They  have  short, 
thick  bodies,  and 
the  abdomen  is  com- 
monly compressed, 
so  that  the  segments 
appear  to  be  more 
or  less  telescoped. 
The  mossy  rose-gall 
[Rhociites  rosae), 
which  forms  a  large, 


Fig.  389.    Mossy  rose-gall  [Ix/ioditc-s  ?vsae) 
(After  Comstock) 


mosslike  gall  on  the  stems  of  roses,  and  the 
spongy  oak-apple  {AmpJiibolips  spongifica), 
which  looks  like  a  puff-ball  on  the  leaves  and 
stems  of  oaks,  are  well-known  examples.  The 
adult  flies  may  be  easily  reared  by  removing 
the  galls  from  the  plants  when  fully  matured 
and  placing  them  in  any  suitable  receptacles. 
Only  a  few  species  are  of  economic  importance 
on  cultivated  crops,  among  which  may  be  men- 
tioned the  pithy  blackberry-gall  {Diastrophus 
nebuIos7is),  an  irregular  swelling  two  to  three 
inches  long  on  blackberry  stems,  inside  which 
will  be  found  numerous  larvae, 

3.   PARASITIC    HYMENOPTERA 

Most  of  the  small,  slender,  wasplike  hymen- 
optera,  which  are  distinguishable  from  the  true 
wasps  by  the  two-segmented  trochanters  of  the 


Fig.  390.  Spongy  oak- 
apple       {Arnphibolips 
spongifica) 

(Photograph  by  Weed) 


'A8 


ELEMENTARY  ENTOMOLOGY 


hind  legs,  are  parasitic  upon  the  eggs  or  larvae  of  other  insects, 
and  belong  to  a  group  of  families  which  are  the  most  important 
of  parasitic  insects.  The  technical  differences 
between  the  more  common  families  are  based 


i^f: 


Fig.  391.  A  gall-fly  (dV 
nips  querciissaliratix), 
which  produces  the 
jumping  galls  formed 
on  oak  leaves.  (Much 
enlarged) 

(After  Kellogg) 


Fig.  392.     Long-tailed  ophion   [Ophion 
iiiacriinnii).    (Much  enlarged) 

(After  Riley) 


upon  the  wing-venation,  and  need  not  be  discussed,  but  the  gen- 
eral habits  are  somewhat  similar.    The  female  lays  her  eggs  either 


Fig.  393.    Pivipla  cotiquisitor.    (Twice  natural  size) 
a,  female  ;  b,  female  in  act  of  ovipositing  in  cocoon  of  tent  caterpillar.    (After  Fiske) 


HYMENOPTERA 


249 


upon  or  within  a  larva  or  an  egg,  the  larger  forms  laying  but  a 
single  egg  on  a  larva,  while  the  smaller  species  may  deposit  a  con- 
siderable number  within  a  large  caterpillar.  The  young  larva  at 
once  enters  the  body  of  the  host  and  feeds  upon  its  blood,  not 
interfering  with  the  principal  tis- 
sues and  organs,  so  that  the  host 
goes  on  growing  and  furnishing 
food  to  the  parasite.  Finally, 
however,  the  parasite  so  depletes 
the  vitality  of  the  host  that  it 
dies,  though  often  not  until  it 
has  transformed  to  a  pupa.  The 
parasitic  larva  then  spins  its  co- 
coon, usually  either  within  or  upon 
the  dead  host,  and  in  due  time 
the  adult  parasite  emerges  and 
continues  the  good  work.    To  a 


Fig.  394.    Long-tailed  ichneumon-fly  {Thalessa  lunator).    (Natural  size) 

The  parts  of  the  long  ovipositor  normally  lie  together  as  a  single  organ  ;  the  figure  at  the  left 
shows  the  manner  of  inserting  the  ovipositor  in  wood.    (After  Comstock) 


certain  extent  many  parasites  are  peculiar  to  certain  host  insects, 
though  many  of  them  attack  various  larvae  or  caterpillars  having 
similar  habits.  Frequently  many  of  our  worst  insect  pests  are 
brought  under  control  by  the  beneficent  work  of  these  little  parasites, 


250 


ELEMENTARY  ENTOMOLOGY 


and  we  are  just  commencing  to  learn  how  to  utilize  them  in  com- 
bating imported  insects.  Thus  the  state  of  Massachusetts  and 
the  United  States  Bureau  of  Entomology  are  now  carrying  on  ex- 
tensive experiments  in  the  importation  of  the  parasites  of  the 
gypsy  and  brown-tail  moths,  which  are  very  largely  effective  in 
holding  those  insects  in  control  in  Europe.  The  various  parasites 
which  attack  the  eggs  and  caterpillars  at  different  stages  of  growth 
have  been  imported ;  they  are  reared  in  this  country  until  suf- 
ficiently numerous,  and  are  then  liberated  in  sections  badly  affected 
by  the  caterpillars,  with  the  hope  that  they  will  ultimately  become 
numerous  enough  to  hold  their  hosts  in  check. 

Ichneumon-flies  (Ichneumonidae).  Any  one  who  has  attempted  to 
rear  any  of  our  large  moths,  such  as  the  cecropia  or  polyphemus 

moths  (see  page  215),  will  have  be- 
come acquainted  with  the  Ophion  flies, 
which  commonly  parasitize  them. 
They  are  light  brown  or  golden  in 
color,  about  three  fourths  of  an  inch 
long,  and  the  abdomen  is  compressed 
laterally,  so  that  the  back  is  ridged. 
A  single  egg  is  laid  on  the  caterpillar, 
which  lives  to  pupate.  The  OpJiion 
larva  spins  a  tough  brown  cocoon 
within  the  pupal  shell  and  emerges 
from  it  the  next  spring.  They  belong 
to  the  large  family  of  ichneumon-flies, 
which  includes  most  of  the  larger  par- 
asites, though  some  of  this  family  are 
quite  small.  The  Pimpla  flies  are  nearly  the  same  size,  but  are 
black  in  color  and  have  the  abdomen  more  broadly  joined  to  the 
thorax.  They  are  effective  parasites  of  many  of  our  most  common 
caterpillars,  such  as  the  tent  caterpillar,  tussock-moth  caterpillars, 
the  cotton-worm,  and  others. 

Braconid-flies  (Braconidae).  Wherever  plant-lice  are  abundant 
there  will  be  found  some  empty  brown  skins,  globular  in  form  and 
with  a  small  round  hole  in  each.  Other  individuals  will  be  brown, 
swollen,  and  dying  as  a  result  of  the  parasitism  of  little  braconid, 
flies  which  are  developing  within  them.   When  mature  the  parasite 


Fig.   395.     Limnet'ia  fugitiva,   £ 

parasite   of  the  tent    caterpillar 

(Twice  natural  size) 

(After  Fiske) 


HYMENOPTERA 


251 


leaves  the  swollen  skin  of  the  aphis  through  a  round  hole.  Often 
whole  colonies  of  aphides  will  be  found  to  have  been  thus  parasi- 
tized. One  little  species  {LysipJilcbus  tritici)  has  been  principally 
responsible  for  subjugating  the  green-bug,  or  southern  grain  aphis, 


P'iG.  396.    Lysiphlebiis  tritici,  male,  the  wasplike  parasite 
of  the  green-bug.    (Very  much  enlarged) 

(After  S.  J.  Hunter) 

which  has  been  so  destructive  to  grain  in  the  southwest ;  this  par- 
asite also  attacks  many  other  commonly  injurious  aphides.  Larvae  of 
the  large  green  tobacco  or  tomato  worm  {PJilegethojituis  qtiinqtte- 
maailata  (Fig.  333) 
are  frequently  found 
covered  with  what 
appear  to  be  small 
silken  eggs.  These 
are  the  cocoons  of 
little  braconids  of 
the  genus  Apantcles 

which     have     devel-     y\g.  397.    Lysiphlebus  parasite  in  act  of  depositing 
oped  within  the  cat-        eggs  in  the  body  of  a  grain  aphis.    (Much  enlarged) 
erpillar's  body.     Not        (After  Webster,  United  States  Department  of  Agriculture) 


2^2 


ELEMENTARY  ENTOMOLOGY 


infrequently  such  caterpillars  are  ruthlessly  destroyed  on  the  sup- 
position that  these  are  the  eggs  of  the  caterpillars,  whereas  they 
are  its  worst  enemies  and  should  always  be  protected.    The  bra- 

conids  are  small,  wasplike  flies,  from  one 
sixteenth  to  one  eighth  of  an  inch  long, 
of  brown  or  yellow-and-black  colors. 


Fig.    398.     Dead    green- 
bugs,  showing  holes  from 
which    parasites    emerge. 
(Much  enlarged) 

The  upper  figure  shows  the  lid 
still  attached,  and  the  lower 
shows  the  parasite  emerging. 
(After  Webster,  United  States 
Department  of  Agriculture) 


Fig.  399.    Wheat-louse  parasite  (Apkidius 
g^-anariaphis  Cook)   and  parasitized  aphid 
from  which  a  parasite  has  emerged.    (Much 
enlarged) 

(Copied  from  J.  B.  Smith) 


Fig.  400.    Sphinx  caterpillar  with  cocoons  of  braconid  parasites 


HYMENOPTERA 


253 


The  chalcis-flies  (Chalcididae)  are  even  smaller,  and  are  usually 
blackish  with  strongly  metallic  reflections  of  bronze  or  green,  and 
are  readily  recognized  by  the  stout  bodies  and  the  almost  entire  ab- 
sence of  wing  veins.  Some  of  them  are  parasitic  on  various  cater- 
pillars.   One  species  i^Ptcronialiis  pupanim)  attacks  the  common 


Fig.  401.    rteromalus  piiparitm,  a  chalcis-fly  which  parasitizes  the  cabbage-worm 
and  many  other  injurious  insects.    (Greatly  enlarged,  hair  line  shows  natural  size) 

(?,  male  ;    /',  female.    (After  Chittenden,  United  States  Department  of  Agriculture) 


cabbage-butterfly  caterpillars,  from  one  of  whose  chrysalids  several 
hundred  of  the  parasitic  flies  may  often  be  reared,  and  in  some  sec- 
tions entirely  prevents  the  increase  of  this  troublesome  garden  pest. 
Many  of  the  species  are  parasitic  in  the  eggs  of  insects,  while  others 
are  the  most  effective  parasites  of  scale  insects.  Unfortunately  one 
or  two  species  are  injurious  to  crops,  the  best-known  example  being 
the  joint- worm  of  wheat 
{Is o soma  tritici),  whose 
larva  works  in  the  lower 
stems,  causing  gall-like 
swellings  of  the  joints 
and  weakening  them  so 
that  the  grain  is  blown 
over,  much  the  same  as 
when  affected  by  the  Hes- 
sian fly. 

Smallest  of  all  the  par- 
asites are  the  little  proc- 
totrypids  {Proctotrypidae), 
the  largest  of  which  are 


Fig.  402 


A  chalcis  parasite  (Chhvpachys  coloti) 
of  the  fruit-tree  bark  beetle 


254 


ELEMENTARY  ENTOMOLOGY 


not  over  one  twenty-fifth  of  an  inch  long,  and  the  smallest  not 
over  one  fifth  that  size.  Most  of  them  inhabit  the  eggs  of  insects, 
though  some  are  secondary  parasites  ;  that  is,  they  are  parasitic 
on  larger  parasites,  and  to  this  degree  are  sometimes  injurious. 


Fig.  403.    The  fig  insect  {Blastophaga  grosso7-inn),  whose  introduction  has  made 
Smyrna  fig  culture  possible  in  California.    (Enlarged) 

a,  adult  female  ;  b,  head  of  same  from  below ;  c^  from  side  ;  d,  male  fertilizing  female ;  e, 
female  igfeuing  from  gall ;  /,  adult  male,    (.\fter  Westwood,  from  Howard) 

Suborder  H.    The  Stinging  Hvmenoptera  {Aculeata) 

In  the  second  suborder  the  female  bears  a  well-developed  sting 
at  the  tip  of  the  abdomen,  which  is  effectively  used  as  an  organ  of 
offense.  The  trochanters  of  the  hind-legs  have  but  a  single  seg- 
ment in  all  of  the  ants,  wasps,  and  bees  which  form  this  suborder. 


1.    THE   ANTS    {FORMICINA) 

A  long  chapter  might  well  be  devoted  to  these  well-known  in- 
sects, for  many  interesting  volumes  have  been  written  by  some  of 
our  greatest  naturalists  concerning  their  remarkable  intelligence 
and  the  highly  developed  organization  of  their  society.^  Every  one 
recognizes  an  ant,  but  the  so-called  white  ants,  or  termites  ( Tenni- 
tidae,  order  Platyptcrd),  and  the  velvet  ants  {JMiitillidac)  may  be 
distinguished  from  them  by  the  fact  that  the  first  segment  of  the 

1  See  the  most  interesting  monograph  of  Dr.  W.  M.  Wheeler,  "Ants,"  Colum- 
bia Biological  Series. 


HYMENOPTERA 


255 


Fig.  404. 


Wheat  straw-worm,  spring 
tion.    (Much  enlarged) 


a,  b,  lar\'ae ;  /,  female,    (.\fter  Riley,  United  States 
Department  of  Agriculture) 


abdomen  of  true  ants  forms  a  sort  of  knot  or  tooth  between  the 

thorax  and  abdomen.   The  males  and  females  are  winged  and  mate 

in  their  nuptial  flight, 
which  may  often  be  ob- 
served on  a  warm  summer 
day,  when  the  air  will  be 
filled  with  them.  After 
this  the  males  soon  die, 
but  the  females  bite  off 
their  wings  and  either 
found  a  new  colony  or  are 
taken  in  by  some  workers. 
The  workers,  or  neuters, 
are  wingless,  undeveloped 
females.  They  may  upon 
necessity  lay  eggs,  but 
these  give  rise  to  males 
only.    The  workers  do  all 

the  work  of  the  colony,  caring  for  the  eggs  and  larvae,  which  they 

feed  and  bring  up  with  all  the  nicety 

of  the  best-ordered  nursery.    The  true 

females,  or  so-called  queens,  merely 

lay  the  eggs,  having  no  control  over 

the  colony,  which  is  managed  on  the 

most  socialistic  lines  by  the  workers. 

There  are  frequently  many  different 

sizes  and  forms  of  workers,  each  of 

which  has  a  particular  sort  of  work. 

Thus  the  large-headed,  strong-jawed 

individuals  are  naturally  the  soldiers, 

while  others  look  after  the  larvae  and 

eggs.    Ants  feed  on  various  animal 

substances,  being  very  fond  of  dead 

insects  and  sweets  of  all  kinds.    It  is 

the    latter    taste    which    leads    many 

species  to  take  such  care  of  the  little      „  a   .    ..    j-         u-j 

^  Fig.  405.   Ants  attending  aphids. 

green  plant-lice  (see  page  127),  which  (Slightly  enlarged) 

give  off  the  sweet  honey-dew  of  which  (Photograph  by  weed) 


256 


ELEMENTARY  ENTOMOLOGY 


they  are  so  fond.  Wherever  aphides  which  produce  honey-dew 
are  abundant,  the  ants  will  be  found  watching  over  them,  warding 
off  parasites  and  often  transporting  them  from  plant  to  plant  when 
food  becomes  scarce.  Now  and  then  an  ant  may  be  seen  to  tap 
an  aphis  with  its  antennae,  when  a  drop  of  the  honey-dew  will  be 
exuded  and  greedily  lapped  up.  So  well  do  they  herd  them  that 
the  aphides  have  been  aptly  called  the  ants'  little  green  cattle.  The 
relation  of  some  ants  to  plant-lice  is  most  remarkable,  as  in  the 
case  of  the  little  brown  ant  {Lasiiis  nigcr  amcricaiuis)  which  cares 
for  the  eggs  of  the  corn  root-aphis  in  its 
a     b     ,<?      J  j-^gg|-    Q^gj.    y^i]-i|-gj-   2,x\^    then    carries    the 

aphides  to  the  roots  of  weeds  and  grasses 
and  then  to  corn  roots  in  the  spring.  It  is 
this  relation  of  the  ants  to  aphides  which 
makes  many  species  of  decided  economic 
importance  to  the  farmer  and  necessitates 
his  destroying  them  as  far  as  possible. 
There  are  several  families  of  ants,  but 
most  of  our  common  forms  are  included 
in  two  large  families. 

The  typical  ants  (Camponotidae)  have  but 
one  segment  to  the  petiole  of  the  abdomen, 
and  have  no  sting.  The  large,  black  car- 
penter-ant {Ca7nponot2is  pennsylvaniciis), 
which  tunnels  out  dead  or  dying  trees, 
logs,  and  timbers,  is  a  well-known  example 
of  one  of  our  larger  species,  and  the  little 
brown  ants  of  the  genus  Lasiiis  make  their 
nests  along  roadways  and  in  pastures  and  meadows,  and  include  the 
species  which  care  for  the  corn  root-aphis  and  other  injurious 
plant-lice.  Some  of  the  species  make  large  mounds  for  their 
homes,  and  others  are  slaveholders,  capturing  the  ants  of  other 
colonies  and  maintaining  them  in  servitude. 

Stinging  ants.  In  the  Myt-inicidae  the  petiole  of  the  abdomen 
is  composed  of  two  segments,  and  most  of  the  females  bear  a  sting. 
The  little  red  ant  {Mojtomoritim  pharaonis)  which  often  infests  our 
pantries  is  well  knoWn,  but  fortunately  has  no  sting.  The  so-called 
agricultural-ants   of  the  southwest  belong  to  this   group.    Their 


Fig.  406.    Lateral  aspects 
of  abdomens  of  three  fam- 
ilies of  ants 

I,  Camponotidae ;  2,  Poncri- 
dae  ;  j,  Mynnicidae ;  a,  tho- 
rax ;  i,  first  abdominal  seg- 
ment ;  c,  second  abdominal 
segment ;  (/,  third  abdominal 
segment.    (After  Kellogg) 


Fig.  407.    The  red  ant  {Mono7?iori!it)i  phanjotiii 
a,  female  ;  b,  worker,    (.-^fter  Riley) 


(Enlarged) 


Fig.  40S.    The  little  black  ant  {Moiioinoriiun  i>ti;iiitin?i).    (Much  enlarged) 

a,  female,  or  queen  ;  b,  same  with  wings  ;  c,  male  ;  d,  workers  ;  e,  pupa  ;  /,  larva  ;  g,  egg  of 
worker.    (After  Marlatt,  United  States  Department  of  Agriculture) 

257 


Fig.  .^09.    The  Argentine  ant  {IriJomyrmex  humilis  Mayr.) 
1?,  worker;  b,  fertile  queen.    (After  Newell) 


Fig.  410.     Mound  nest  of  western  agricultural-ant   [Pogonomymtex  occideutalis 
Cress.),  showing  entrance  hole  in  mound,  and  cleared  space  around  it 

(After  Headlee  and  Dean) 

258 


HYMENOPTKRA 


259 


nests  are  made  underground,  and  around  the  entrance  all  vegeta- 
tion is  cleared  off  and  regular  runways  radiate  out 


Fig.  411.  Western  agricultural-ant, 
or  mound-building  prairie  ant  {Poiro- 
nomyrmex  occiJentalis).     (Enlarged) 

a,  worker:    b,  queen.     (After  Headlee 
and  Dean) 


among  the  neighboring  grasses,  the  seeds 
the  nest  and  furnish  food.  A  few  years  ago 
into  New  Orleans  from  Argentina,  known  as 
the  Argentine  ant  (Iridomyt-mex  Juimilis), 
and  has  now  spread  over  Louisiana  and 
neighboring  states,  becoming  a  ver\-  serious 
household  pest  as  well  as  attacking  vegeta- 
tion. Another  common  species  of  this  fam- 
ily {Solenopsis 
geminata)  is 
one  of  the 
most  impor- 
tant enemies 
of  the  lar\ae  of 
the  cotton-boll 
weevil.  It  will 
thus  be  seen 
that  our  com- 
mon ants  are 
of  ver)-  diverse 
habits  and  of 
var}ing  eco- 
nomic impor- 
tance. They 
are  much  more 
abundant      in 


of  which  are  stored  in 
a  species  was  imported 


Fig.    412.       Solenopsis   geminata 
Fab.,  a  native  ant  which  is  a  val- 
uable  enemy  of   the   cotton-boll 
weevil.    (Much  enlarged) 

(After    Hunter   and    Hinds,    United 
States  Department  of  Agriculture) 


Fig.   413.     Work    of    the 

black  carpenter-ant  (Cam- 

poiiotus  pennsylvanicits)  in 

black  spruce 

The  injury  to  the  living  tree 
allowed  the  ants  to  enter,  so 
that  the  heamvood  was  com- 
pletely destroyed  by  them  and 
the  tree  fell.   (After  Hopkins) 


26o 


ELEMENTARY  ENTOMOLOGY 


the  South,  and  in  the  tropics  become  veritable  pests.  Various  arti- 
ficial nests  have  been  devised  whereby  colonies  may  be  maintained 
indoors  for  study,  for  which  no  insects  are  of  more  interest.^ 


2.  WASPS 


Every  small  boy  soon  makes  the  acquaintance  of  the  bees  and 
wasps,  which  he  naturally  classes  together  from  their  ability  to  sting 
most  painfully.    The  males,  however,  are  entirely  harmless,  but 


Fig.  414.    A  digger-wasp  {Ainniophila  sp.).    (Natural  size) 

a,  wasp  putting  an  inch-worm  into  its  nest  burrow ;  h^  tlie  nest  burrow  with  food  for  the 

young,  paralyzed  inch-worms  in  bottom  and  burrow  nearly  filled  ;  c,  wasp  bringing  a  bit  of 

material  to  put  over  the  filled  nest  burrow.    (From  life,  after  Kellogg) 

unfortunately  we  have  no  means  of  recognizing  them  in  the  field. 
The  wasps  may  be  distinguished  from  the  bees  by  the  first  seg- 
ment of  the  hind  tarsus  being  cylindrical  and  naked,  and  the  body 
hairs  being  simple  and  unbranched. 

Digger-wasps  {Sphecind).    Several  families  of  wasps  are  grouped 
together  under  this  name,  which  is  due  to  their  habit  of  digging 


1  See  Kellogg's  "American  Insects,"  p.  548. 


HYMENOPTERA 


261 


holes  in  the  ground  or  in  wood,  in  which  their  nests  are  made. 
They  are  distinguished  from  the  true  wasps(  [  rj;?^z';/«)  by  the  wings 
lying  flat  on  the  body  when  at  rest.  They  are  solitary  forms,  each 
female  making  her  own  nest  in  which  the  eggs  are  laid,  and  pro- 
visioning it  with  spiders,  caterpillars,  or  other  insects,  upon  which 
the  larvae  feed.  The  food  is  stored  alive  in  a  remarkable  manner. 
The  female  seizes  the  spider  or  insect  and  stings  it  in  the  nerve 
ganglia  of  the  thorax,  thus  paralyzing  it  so  that  it  remains  alive 
but  helpless.  The  prey  thus  para- 
lyzed is  placed  in  the  burrow,  the 
egg  is  laid  with  it,  and  the  tube  is 
then  sealed  up,  several  compart- 
ments usually  being  made,  one  after 
another.  When  the  egg  hatches, 
the  young  larva  finds  an  abundant 
supply  of  well-preserved  food  for 
its  nourishment.  Many  of  the  nests 
are  made  in  burrows  in  sandy  banks, 
others  in  the  pith  of  plants,  such  as 
the  sumac  and  elder,  while  others 
make  mud  nests  or  tubes,  as  do  the 
common  mud  daubers. 

Velvet-ants  (Mutillidae).  In  the 
warmer  parts  of  the  country  one 
will  often  see  large,  antlike  insects 
thickly  covered  with  black,  red,  or 
yellow  hair,  which  has  given  them 
this  name.  The  males  are  winged, 
but  the  females  are  wingless  and  can  sting  severely.  One  of  the 
largest  species  is  bright  scarlet  and  black,  two  thirds  of  an  inch 
long,  and  provisions  its  burrows,  made  in  beaten  paths,  with  flies 
and  other  insects,  though  it  is  known  to  enter  beehives  and 
kill  bees. 

The  spider-wasps  (Psammocharidae)  are  slender,  long-legged, 
blackish  wasps  with  reddish  or  black  wings,  the  body  often  marked 
with  red  or  orange  ;  they  provision  their  nests  with  spiders.  They 
are  mostly  medium-sized  wasps,  though  the  tarantula  hawk  {Pepsis 
formosa),  which  preys  upon  the  tarantulas  of  the  southwest,  is 


Fig.   415.     A   velvet-ant   {Sphaero- 

phthalma  siniilima),  female.    (Four 

times  natural  size) 

(After  Lugger) 


262 


ELEMENTARY  ENTOMOLOGY 


the  largest  species  of  the  order,  being  nearly  two  inches  long 
and  having  a  wing  expanse  of  over  three  inches.  Not  infrequently 
it  is  overpowered  and  destroyed  by  its  formidable  prey. 


Fig.  416.    The  tarantula-killer  {Pepsis  formosa).    (Natural  size) 

The  thread-waisted  wasps  (Sphecidae)  are  readily  recognized  by 
the  very  long,  threadlike  petiole  of  the  abdomen,  and  include  our 
common  mud-daubers,  which  make  their  nests  under  the  eaves  of 

buildings  and  in  barns,  attics,  etc. 


The  nests  are  composed  of  sev- 
eral tubes  placed  side  by  side, 
each  of  which  is  provisioned 
with  spiders.  They  may  be  seen 
around  pools,  collecting  mud  for 
their  nests,  and  jerking  their 
wings  from  side  to  side  in  a 
nervous  manner. 

A  nearly  related  family  {Beni- 
becidac),  which  burrows  in  the 
sand  and  provisions  its  nests  with 
flies  and  similar  insects,  includes 
the  large  cicada-killer.     This  is 


Fig.  417. 


A   mud-dauber    {Pelopaeus 
cetneiitariiis) 

(After  S.  J.  Hunter) 


HYMENOPTERA 


263 


one  of  our  largest  wasps,  one  and  one  fourth  inches  long,  black 
or  rusty  in  color,  with  the  abdomen  banded  with  yellow,  which 
pounces  upon  a  cicada  and  carries  it  off  to  its  burrow  in  the  ground 
as  food  for  the  larva.  Other  nearly  related  families  of  digger-wasps 
make  their  nests  in  the  pith  of  plants  or  bore  into  more  solid 


Fig.  418.    Mud-dauber  wasp  {Pelopaeiis  sp.)  and  nest.    (Natural  size) 
(After  Linville  and  Kelly) 

wood,  or  often  use  the  deserted  burrow  of  some  other  insect  (such 
as  some  of  the  bees  which  have  similar  habits),  provisioning  them 
with  flies,  spiders,  and  various  insects. 

The  true  wasps  (Vespina)  may  be  distinguished  from  the  digger- 
wasps  by  having  the  wings  folded  on  the  back  like  a  fan  when  at 
rest,  and  the  legs  are  not  adapted  to  burrowing,  being  free  from 
spines  and  bristles.   The  solitary-wasps  {Enmenidae)  resemble  the 


264 


ELEMENTARY  ENTOMOLOGY 


digger-wasps  in  their  habits,  making  burrows  in  the  earth  or  in 
wood,  or  forming  their  nests  of  mud  and  provisioning  them  with 

insects.  (3ne  of  our  common 
species  {Euvicnes  fratermis) 
makes  a  little  mud  nest  on 
the  twigs  of  bushes  and  trees, 
which  looks  like  a  miniature 
water-jug.  The  young  are  fed 
on  caterpillars,  and  enjoy 
cankerworms  when  these  are 
available.  Other  species  of 
this  family  look  like  small  yel- 
low-jackets. The  Social- wasps 


Fig.  419.    Female  Sphecius  spcciosus  carry- 
ing cicada  to  her  burrow.    (Natural  size) 

(After    Riley,    United    States    Department     of 
Agriculture) 


( ]  ^espidac)  live  in  colonies  and,  be- 
sides males  and  females,  have  a 
form  of  undeveloped  females  known 
as  workers,  all  of  which  are  winged. 
They  build  their  nests  either  in  the 
ground  or  attached  to  bushes,  trees, 
or  buildings,  and  construct  them  of 
paper  made  from  bits  of  wood  chewed 
up  and  formed  into  a  paste,  for  they 
discovered  the  possibility  of  making 
paper  from  wood  pulp  long  before 
man  thought  of  it.  They  are  very 
jealous  of  their  homes  and  enforce 
a  wholesome  respect  for  them  upon 
whoever  even  accidentally  disturbs 
them,  as  every  one  who  has  attacked 
a  nest  of  yellow-jackets  or  hornets  is 


Fig.    420.     The    fraternal    potter 

wasp  {Einnoies fraiefuiis)  and  its 

earthen  nest 

(Photograph  by  Weed) 


Fig.  421.    Poiisies  annularis  and  its  nest.    (Two  thirds  natural  size) 
(After  Quaintance  and  Brues,  United  States  Department  of  Agriculture) 


Fig.  422.    Nest  of  yellow-jacket  {]~espa  sp.) ;  at  right,  nest  opened  to  show  combs 

(Photograph  by  Weed) 

265 


266 


ELEMENTARY  ENTOMOLOGY 


Fig.  423.     White-faced  wasp 
(I'e.spa  iiiaciilata) 


well  aware.    The  adults  are  predacious  and  feed  their  young  on 

insects  which  have  been  masticated.     Not  infrequently,  where  an 

outbreak  of  caterpillars  occurs,  wasps 
will  be  seen  carrying  them  off  to  their 
nests  in  considerable  numbers ;  we 
have  observed  them  at  work  on  the 
cotton  boll-worm  and  leaf-worms  in 
the  South.  But  two  genera  are  com- 
mon in  the  East.  Polistcs  are  black 
ringed  with  yellow,  or  are  brownish, 
and  have  long,  spindle-shaped  abdo- 
mens.   Their  nests  are  composed  of  a 

single  comb  and  are  attached  by  a  short  stem.  The  genus  Vespa 

includes  the  hornets  and  yellow-jackets,  which  are  black,  spotted 

or  banded  with  yellow,   or  yellowish-white, 

with  a  short,  stout  body,  and  the  abdomen 

attached  by  a  very  short  peduncle.     Their 

nests  are  formed  of  several  layers  of  combs, 

all  of  which  are  covered  with  a  waterproof 

covering  of  paper,  made  from  weatherworn 

wood  of  stumps,  trees,  fences,  and  buildings. 

The  nests  are  gradually  enlarged,  new  combs 

being  added  and  the 

outer  envelope  being 

enlarged      to      cover 

them.  The  males  and 

workers  die  in  the  fall, 

and  the  females  hiber- 
nate over  winter  and 

start  a  new  colony  in 

the  spring. 


3.  BEES  [APINA) 

Most  of  our  com- 
mon bees  are  readily 
distinguished  as  such 
by  the  general  shape 
and  hairy  clothing  of 


Fig.  424.  (7,  mouth-parts  of  a  short-tongued  bee 
{Pivsopis  piibescens)  (note  short,  broad,  fiaphke 
tongue,  or  glossa) ;  b,  mouth-parts  of  a  long-tongued 
bee  {Anthophora  pilipes)  (note  greatly  extended 
tongue).    (Much  enlarged) 

(After  Sharpe,  from  Kellogg) 


HYMENOPTERA 


267 


the  body.  Some  of  them,  however,  may  be  confused  with  some  of 
the  wasps,  from  which  they  may  be  separated  by  the  structure  of  the 
first  segment  of  the  hind  tarsus  (which  is  dilated,  flattened,  and 
usually  provided  with  numerous  hairs 
to  aid  in  carrying  pollen)  and  also  by 
the  fact  that  the  body  hairs  are  covered 
with  short  branches  instead  of  being 
simple,  as  in  wasps.  They  are  quite 
variable  in  habit :  some  are  solitary,  — 
that  is,  each  female  makes  a  nest  for  her 
young,  as  do  the  solitary  wasps  ;  others 
lay  their  eggs  in  the  nests  of  other  bees  ; 
while  others,  of  which  the  honey-bee  is 
the  best  example,  live  in  colonies.  The 
nests  may  always  be  recognized,  how- 
ever, by  their  being  stored  with  pollen 
and  honey  and  never  with  insects.  Two 
families  are  recognized,  which  are  dis- 
tinguished by  the  length  of  the  tip  of 
the  labium,  or  glossa. 

In  the  Short-tongued  bees  {Andre- 
nidac)  the  tip  of  the  labium  is  shorter 
than  the  base,  while  in  the  Long-tongued 
bees  (Apidae)  it  is  much  longer  and  en- 
ables them  to  secure  the  nectar  from 
deeper  flowers.  All  of  the  bees  are  of 
great  economic  importance,  for  as  they 
go  from  flower  to  flower  the  pollen  be- 
comes attached  to  the  hairs  of  the  body 
as  well  as  to  the  special  structures  on  the 
legs,  by  which  they  transport  it,  and  is 
brushed  off  on  the  stigma  of  the  next 
flower  visited.  Thus  the  bees  are  the 
most  important  agents  in  the  cross-fer- 
tilization of  flowers,  without  which  many  plants  will  not  set  their  seed 
or  fruit.  For  this  reason  those  who  grow  cucumbers  and  tomatoes 
under  glass  always  have  a  hive  of  bees  to  fertilize  the  flowers,  and 
where  bees  are  scarce,  many  of  our  common  fruits  set  but  sparingly. 


Fig.  425.    Nest  of  Aiidrena, 
the  mining  bee 

(After  Packard) 


268 


ELEMENTARY  ENTOMOLOGY 


Fig.  426.     A  common 

short-tongued  bee  (A/i- 

drena    sp.).       (Slightly 

enlarged) 


None  of  the  short-tongued  bees  hve  in  colonies,  and  many  of 

them  make  their  nests  in  the  ground,  which  has  given  them  the 
name  of  "mining  bees."  Their  tunnels  are 
usually  branched,  each  branch  terminating  in 
a  single  cell,  which  is  lined  with  a  sort  of 
glazing.  After  this  cell  is  filled  with  nectar 
and  pollen,  the  ^g^  is  laid  and  the  cell  is  then 
sealed  up.  Quite  commonly,  large  numbers 
of  these  tunnels  will  be  found  near  together, 
forming  large  villages.    Some  of  the  smaller 

forms  mine  into  the  sides  of  sand  banks  and 

cliffs,  their  numerous  holes  making  the  surface 

appear  as  if  it  had  received  a  charge  from  a 

shotgun.    These  little  females  of  the  genus 

Halictiis  have  the  interesting  habit  of  making 

a  common  burrow  into  a  bank  and  then  each 

making  a  side  passage  to  her  own  cells,  so 

that,   as   Professor   Comstock  aptly  remarks, 

"While  Andrcna  builds  villages  composed  of  individual  homes, 

Halictns  makes  cities  composed  of  apartment  houses." 


Fig.  427.     A  mining- 
bee  {Ha  I  ictus  lerouxii 
var.     nthomm    Ckll.). 
(Slightly  enlarged) 


Fig.  428.    The  leaf-cutter  bee  and  a  leaf-covered  cell  removed  from  its  burrow. 

(Natural  size) 

(After  Linville  and  Kelly) 


HYMENOPTERA 


269 


The  majority  of  the  Long-tongued  bees  (Apidac)  are  soHtary  and 

have  most  diverse  nesting  habits :  some  make  their  cells  in  the 
ground,  as  do  the  miners  ;  others  are  potters,  and 
fashion  nests  of  mud,  which  are  attached  to  the 
stems  of  plants  ;  some  are  carpenters,  boring  holes 
in  wood  ;  while  some  go  so  far  as  to  upholster 
their  nests  with  neatly  cut  pieces  of  leaves,  with 
which  the  cells  are  lined  and  covered.  The  leaf- 
cutter  bees  are  peculiarly  interesting  forms,  though 
of  no  particular  economic  importance.  They  bore 
a  hole  in  soft  or  decaying  wood,  in  the  bottom  of 
which  is  deftly  fitted  a  piece  of  a  leaf,  rose  leaves 
being  commonly  used,  so  as  to  make  a  thimblelike 
cup.  In  this  the  pollen  and  nectar  are  placed  and 
an  egg  is  laid,  and  then  a  circular-shaped  piece  of 
leaf  is  jammed  down  so  as  to  make  a  tight  wad 
over  the  cell,  and  another  similar  cell  is  made 
above  it.  The  circular  areas  cut  from  rose  leaves 
b\'  these  bees  may  frequently  be  noticed.  Others 
are  known  as  carpenter-bees,  making  their  nests 
in  wood.  The  smaller  carpenter-bee  {Ceratitia 
ditpla)  inhabits  the  dead  stems  of  sumac  or  the 
hollow  stems  of  other  plants,  which  are  cleaned 
out  and  used  over  again  by  the  young.  Several 
cells  are  made  and  separated  by  little  chips.  When 

the  tunnel  is  full,  the  female  waits  for  her  children  to  grow  up. 

"  The  lower  one  hatches  first,"  says  Professor  Comstock,  "  and  after 

it    has    attained    its 

growth,  it  tears  down 

the    partition    above 

it,    and    then    waits 

patiently  for  the  one 

above  to  do  the  same. 

Finally,  after  the  last 

one  in  the  top  cell  has 

matured,  the  mother  ^.^  ^3^  ^^  carpenter-bee  (Xylocopa  caroUna  Linn.) ; 
leads  forth  her  full-  b,  first  segment  of  hind  tarsus  ;  c,  same  of  bumble-bee 
fledged  famil\-  in   a  (After  Waish) 


Fig.   429.     Nest 

of  carpenter-bee. 

(Reduced) 

(After  Jordan  and 
Kellogg) 


270 


ELEMENTARY  ENTOMOLOGY 


flight  into  the  sunshine."  The  larger  carpenter-bee  {Xylocopa 
virginicd)  closely  resembles  a  bumble-bee,  being  fully  as  large, 
yellow  and  black  in  color,  with  a  metallic  blue  reflection  on  the 
abdomen.  It  excavates  its  nests  in  solid 
wood,  often  boring  for  a  foot  or  more. 

Many  of  the  long-tongued  bees  are  known 

as  guest-bees,   from  their    habit   of   laying 

their  eggs  in  the  cells  of  other  bees,  which 

rear  the  larvae  of  the  intruders  as  they  do 

their  own.    The  largest  of  these  {Psythiriis) 

so  closely  resemble  bumble-bees  that  it  is 

difficult  to  distinguish  them  from  the  males, 

though  the  females  are  readily  recognized 

from  their  lacking  the  pollen-basket  borne 

by  the  hind-legs  of  the  bumble-bees.  Just 

why  they  are  tolerated  is  a  mystery,  for  the 

I     bumble-bees  allow  them  to  go  in  and  out 

of  their  nests  with  the  greatest  freedom. 

The  social  bees  include  our 

common    bumble-bee    and    the 

domesticated  honey-bees.    The 

bumble-bees  are  of  considerable 

importance  to  the  farmer,  for 

they  are  the  only  ones  whose 

tongues  are  long  enough  to  feed 

TTrr.   .-,T    AT^cf  „f  K     ui^  k^^  m    h        on  red-clover  blossoms,  so  that 

1"IG.  431.    JNest  01  bumble-bee  (Bombiis  ' 

sp.),  showing  opening  at  the  surface  of     they  are  entirely  responsible  for 
the  ground  and  also  brood  cells  in  the     jj-g  pollination,  and  where  they 

cavity  beneath  .    .      ,.„^      , 

are  scarce  it  is  ditticult  to  secure 

(Adapted  from  McCook  by  Kellogg)  r       1  1         t       • 

a  crop  01  clover  seed.  It  is 
hardly  necessary  to  describe  the  nest  of  a  bumble-bee,  for  what 
country  boy  does  not  look  back  upon  the  stirring  experiences  in- 
cident to  the  robbing  of  their  nests,  or  of  accidentally  disturbing 
one  while  mowing,  and  being  given  good  reason  to  remember  the 
fact.  The  queens  are  larger  than  the  males  or  workers,  and  are 
the  only  forms  which  live  over  winter.  In  the  spring  the  queen 
finds  some  deserted  mouse  nest  and  within  it  places  a  ball  of  pol- 
len and  her  eggs.    The  larvae  feed  on  the  pollen  and,  when  full 


HYMENOPTERA 


71 


a 


Fig.  432.    Jiumble-bees 

a,  worker;  /',  queen,  or  fertile  female.    (After  Jordan 
and  Kellogg) 


grown,  make  strong,  brown,  silken  cocoons,  in  which  they  change 
to  pupae.   These  cocoons  are  strengthened  with  wax  by  the  queens, 

and  are  used  for  storing 
honey,  after  the  young 
emerge.  The  first  broods 
are  all  workers,  and  af- 
ter their  appearance  the 
queen  has  nothing  more 
to  do  but  lay  her  eggs. 
Later  in  the  season  the 
males  and  other  queens 
appear,  all  living  together 
in  the  same  nest.  In  the 
fall  the  young  queens 
crawl  away  to  a  suitable 
hibernating  place,  and  in 
the  spring  start  new  colonies,  in  the  manner  previously  described. 
Honey-bees.  Probably  no  other  insect  is  of  quite  as  much  human 
interest  as  the  honey-bee.  Apiculture  is  a  well-developed  art,  its 
hterature  is  extensive,  and  its  devotees  have  well-organized  associ- 
ations. The  honey-bee  was 
brought  from  Europe  by 
the  early  settlers  of  this 
country,  and  swarms  have 
escaped,  which  have  become 
the  wild  bees  now  found  in 
hollow  trees.  There  are 
three  forms  in  every  hive, 
—  the  queen,  the  drones,  or 
males,  and  the  workers, 
which  are  imperfectly  devel- 
oped females.  The  workers 
are  the  common  forms  with 
which  we  are  familiar,  and  which  do  all  the  work  of  the  colony.  The 
drones  are  larger  than  the  workers,  are  reared  in  larger  cells,  and  are 
blunter  and  broader  in  shape.  They  are  relatively  few  in  number, 
and  occur  only  in  the  early  summer,  during  the  swarming  season, 
after  which  they  are  expelled  from  the  nest  or  killed  by  the  workers. 


Fig.  433.    The  honey-bee  {A/>/s  mellifica) 
.{,  queen  ;  B,  drone  ;  C,  worker.    (After  Kellogg) 


272 


ELEMENTARY  ENTOMOLOGY 


The  queen  bee 
is  much  larger 
than  the  work- 
er, and  has  a 
long,  pointed 
body.  She  is 
developed  in  a 
special  cell  sev- 
eral times  the 
size  of  an  or- 
dinary cell  and 
readily  distin- 
guishable, as  it 
extends  at  a 
right  angle  to 
the  other  cells. 
The  larvae  are 
all  fed  by  the 

workers,  who  provide  honey  and  bee-bread,  composed  of  pollen  and 
nectar,  for  the  ordinary  cells  which  are  to  develop  workers  and 


Fig.  434.   Queen  cells  of  the  honey-bee,  and  worker  brood  in 
various  stages 

(After  Benton,  United  States  Department  of  Agriculture) 


Fig.  435.    Honey-bees  building  comb  (side  of  hive  removed) 
(After  Benton,  United  States  Department  of  Agriculture) 


HYMENOPTERA 


273 


drones,  but  for  the  queen  cell  a  royal  jelly,  which  is  excreted  from 
the  mouths  of  the  workers  and  is  very  nutritious.  Any  worker  egg 
may  be  developed  into  a  queen 
at  the  desire  of  the  workers 
by  enlarging  the  cell  and  feed- 
ing the  larva  with  this  royal 
jelly.  In  the  spring  new 
queens  appear  in  the  colony, 
which  are  defended  from  the 
old  queen  by  the  workers, 
when  the  old  queen,  with 
many  of  her  subjects,  forms 
a  new  swarm  and  goes  off 
to  start  a  new  colony,  thus 
insuring  the  multiplication 
and  continuance  of  the  spe- 
cies. The  comb  is  made  of 
wax,  and  is  constructed  in 
thin,  hexagonal  cells  so  as 
to  use  as  little  material  as 
possible,  for  it  takes  twenty- 
one  pounds  of  honey  to  make 
one  pound  of  wax.  To  secure 
the  wax,  some  of  the  workers 
gorge  themselves  with  honey 
and  hang  in  a  curtainlike  mass 
in  the  hive.  In  a  day  or  so  the 
wax  commences  to  exude 
from  the  wax  plates  on  the 
underside  of  the  abdomen 
and  is  scraped  off  and  used 
by  other  workers  in  construct- 
ing the  comb.  From  the  buds 
of  various  trees,  particularly 
the  poplar,  they  collect  a 
sort  of  resin,  called  propolis, 
which  is  used  for  cementing 
crevices    in    the    hive.     The 


Fig.  436.    Legs  of  the  honey-bee 

.-/,  left  front  leg  of  worker  (anterior  view),  show- 
ing position  of  notch  (M)  of  antenna  cleaner 
on  base  of  first  tarsal  joint  (/  Tar)  and  of  clos- 
ing spine  (cc)  on  end  of  tibia  (77^)  ;  B,  left 
hind-leg  of  worker  (anterior  view),  showing  the 
pollen-basket  (67')  on  outer  surface  of  tibia 
(Ti)  ;  C,  inner  view  of  first  tarsal  joint  of  hind- 
leg  of  worker,  showing  rows  of  pollen-gather- 
ing hairs  and  the  so-called  "  wax  shears." 
(After  Snodgrass,  United  States  Department 
of  Agriculture) 


2  74         ELEMENTARY  ENTOMOLOGY 

bee-bread  on  which  the  larvae  are  fed  is  made  from  the  pollen  of 
flowers  and  is  carried  to  the  nest  on  the  hind-legs,  which  have  a 
hair-encircled  area,  called  the  pollen-basket,  for  transporting  it. 
The  honey  is  stored  for  food  during  the  winter,  and  is  made  from 
the  nectar  of  flowers,  which  is  taken  into  the  honey-stomach,  where 
it  is  changed  to  honey,  and  is  then  regurgitated  into  the  cells  of 
the  comb. 

Summary  of  the  Hymenoptera 

Suborder  I.   Boring  Hymenoptera  {Terebratitia).     With  ovipositor  and  two- 
segmented  trochanters. 
Section  I.   Plant-eating  Hymenoptera.    Abdomen  not  constricted. 
Family.    Saw-flies  {Tenthredinidae). 
Horn-tails  {Siricidae). 
Section  2.   Gall-inhabiting  Hymenoptera  {Cynipidae). 
Section  3.   Parasitic  Hymenoptera.    Abdomen  petiolate. 
Family.    Ichneumon-flies  (IcJmeiimonidae). 
Braconid-flies  {Braconidae). 
Chalcis-flies  {Chalcididae). 
Proctotrypid-flies  {Proctotiypidae). 
Suborder  II.   Stinging  Hymenoptera  {Aculeata).     Females  bearing  a  sting; 
simple  trochanters. 
Section  i.  Ants  (superfamily  Fo)-)nicind). 
Family.    Common  ants  (Camponotidae). 
Stinging  ants  {Myrmicidae). 
Section  2.  Wasps.    First  segment  of  metatarsi  cylindrical  ;  hairs  simple. 

A.  Digger-wasps  (superfamily  Sphecina). 

Family.    Velvet-ants  {Mutillidae). 

Spider-wasps  {Psatumocharidae). 
Thread-waisted  wasps  (SpJiecidae). 
Bembecids  {Bembecidae\ 
and  others. 

B.  True  wasps  (superfamily  Vespina).    Wings  folded  fanlike  on 

back  when  at  rest. 
Family.    Solitary  wasps  {Eujuenidae). 
Social  wasps  {Vespidae). 
Section  3.    Bees  (superfamily  Apina).     First   segment   of   metatarsi, 
broad,  flattened,  hairy ;  body  hairs,  plumose. 

Family.    Short-tongued  bees  {Andrenidae). 
Long-tongued  bees  (Apidae). 

Solitary  bees,  guest-bees,  social  bees. 


PART   III.    LABORATORY   EXERCISES 

CHAPTER  XVI 

THE  EXTERNAL  ANATOMY  OF  THE  LOCUST 

Note.  Beyond  a  doubt,  one  of  the  most  difficult  problems  every  instructor  in 
the  biological  laboratory  has  to  meet  is  to  determine  the  amount  of  assistance 
which  shall  be  given  individual  students.  In  advanced  work,  probably  the  best 
plan  is  to  train  students  to  rely  on  their  own  resources  and  to  solve  their  own 
problems.  In  elementary  classes,  however,  far  too  much  time  is  often  wasted  in 
the  laboratory  because  the  instructor  does  not  happen  to  be  at  hand  to  aid  and 
direct  the  student.  For  this  reason  the  following  instructions  are  given,  more  or 
less  in  detail,  with  the  hope  that  the  students  may  intelligently  carry  on  their 
work  without  the  constant  attention  of  the  instructor. 

In  order  to  derive  the  most  benefit  from  the  laboratory  work,  it  is  essential 
that  the  students  should  verify  every  detail  of  structure  herein  given  before  pro- 
ceeding with  the  drawings,  the  latter  being  considered  simply  as  a  means  to  an 
end.  In  fact,  the  amount  of  good  derived  by  the  student  from  the  laboratory  work 
is  largely  dependent  upon  the  energy  of  the  individual.  For  this  reason  the  lab- 
oratory work  should  not  be  judged  entirely  by  the  drawings,  and,  if  possible,  the 
actual  amount  of  information  obtained  by  the  student  in  the  laboratory  should  be 
determined  by  examinations  similar  to  those  given  in  lecture  or  recitation  work. 

For  details  concerning  laboratory  methods  and  equipment,  see  Chapter  XXIII. 

Section  I,    External  Anatomy  of  the  Grasshopper  (Type 
OF  Class  Insecta) 

Material.  The  red-legged  locust  {Melanoplus  femi(i--rubruni)  has  been 
selected  as  the  type  of  the  class  Insecta,  partly  on  account  of  its  abundance 
and  the  ease  with  which  it  may  be  collected,  and  partly  on  account  of  its 
simplicity  of  structure.  Specimens  for  class  work  should  be  collected  in  the 
late  summer  or  early  fall,  and  preserved  in  85  per  cent  alcohol  for  three  or  four  >- 
days.  After  this  time  has  elapsed,  they  should  be  transferred  to  80  per  cent  ^ 
alcohol,  to  which  10  per  cent  of  pure  glycerin  has  been  added.  If  soaked  in  p: 
warm  water  a  short  time  before  using,  the  specimens  will  be  rendered  soft  and  « 
pliable.    The  students  should  verify  the  following  points :  q 

1.    Body  covering.    Carefully  examine  with  a  hand  lens  the  body    "b 
covering  of  the  specimen,  and  note  that  it  is  made  up  of  a  series 

27  s 


0 


276         ELEMENTARY  ENTOMOLOGY 

of  hardened  plates.  These  plates  are  known  as  sclerites,  and  the 
depression  between  two  plates  is  called  a  suture.  The  hardness 
of  the  plates  is  due  to  the  deposition  of  a  horny  substance  called 
chitin. 

2.  General  divisions  of  the  body.  Typically  the  bodies  of  all 
insects  are  divided  into  a  series  of  rings,  or  segments.  In  many 
places  two  or  more  of  these  rings  have  grown  together,  or  are  fused. 
Again,  in  certain  regions  of  the  body,  parts  of  the  segments  may  be 
lost.  Regardless  of  the  amount  of  variation  in  this  respect,  however, 
we  find  that  the  segments  are  always  grouped  into  three  regions, 
known  as  head,  thorax,  and  abdomen. 

a.  The  head.  The  head  is  made  up  of  a  number  of  segments, 
which  are  fused  together,  forming  a  boxlike  structure.  On  the 
head  are  found  the  eyes,  mouth-parts,  and  antennas. 

b.  TJie  thorax.  This  is  the  second  division  of  the  body,  and 
consists  of  three  segments,  known  as  the  prothorax  (division  nearest 
the  head),  mesothorax,  and  metathorax.  Each  of  these  segments 
bears  a  pair  of  walking  appendages,  and  in  addition  the  meso- 
thorax and  metathorax  are  provided  with  wings. 

c.  71ie  abdomen.  This  is  the  third  division  of  the  body,  and  is 
made  up  of  eleven  segments.  The  posterior  segments,  however, 
are  not  complete,  showing  modifications. 

Exercise  1.  Pin  the  specimen  to  the  bottom  of  a  dissecting  dish,  spread  the 
wings  and  wing-covers  of  one  side,  and  make  an  enlarged  drawing  (dorsal  view) 
of  the  entire  insect,  showing  the  above-named  divisions. 

3.  Detailed  study  of  the  head.  As  already  noted,  the  head  of  the 
locust  is  made  up  of  a  number  of  segments  which  have  been  firmly 
fused  together.    The  following  divisions  should  be  noticed  : 

a.  The  epicrarimm.  This  is  a  boxlike  piece  which  surrounds  the 
eyes  and  forms  the  basis  of  attachment  for  the  movable  parts  of 
the  head.  It  extends  down  the  front  of  the  head,  between  the  eyes, 
to  the  transverse  suture,  and  down  the  sides  of  the  head  to  the 
base  of  the  mouth-parts.  The  sides  of  the  epicranium  below  the 
compound  eyes  are  known  as  the  genae,  or  cheeks,  while  the  front 
of  the  head  between  the  compound  eyes  is  called  the  frons. 

b.  The  eonipojind  eyes.  These  are  situated  upon  the  upper  por- 
tion of  the  sides  of  the  head,  and  are  large,  brown,  oval  areas  with 


THE  EXTERNAL  ANATOMY  OF  THE  LOCUST      277 

smooth,  highly  poHshed  surfaces.  If  examined  with  a  lens,  the 
surface  will  be  seen  to  be  made  up  of  a  number  of  hexagonal 
areas,  which  are  known  as  facets. 

c.  The  ocelli.  These  are  sometimes  called  the  simple  eyes,  and 
consist  of  three  very  small,  almost  transparent  oval  areas.  One  of 
the  ocelli  is  situated  on  the  front  of  the  head  just  below  the  lowest 
margin  of  the  compound  eyes  ;  the  other  two  are  placed  in  the 
top  of  the  impression  which  contains  the  bases  of  the  antennas, 
and  in  contact  with  the  upper  portion  of  the  compound  eyes. 

d.  The  aiiteiuHC.  These  are  two  long,  threadlike  processes  situ- 
ated median  to  the  compound  eyes.  Each  consists  of  about  twenty- 
six  segments.  Each  antenna  arises  from  an  oval  depression  known 
as  the  antennary  fossa,  and  is  attached  by  a  thin  membrane  which 
admits  of  motion  in  all  directions. 

e.  TJie  clypeus.  This  is  a  short,  rectangular  piece  attached  to 
the  lower  straight  edge  of  the  epicranium. 

f .  TJte  mouth-parts.  These  consist  of  a  number  of  separate  parts 
attached  to  the  ventral  region  of  the  epicranium,  and  will  be 
studied  in  detail  later. 

Exercise  2.  Make  an  enlarged  drawing  of  the  front  of  the  head,  showing 
the  above  parts. 

Exercise  3.  Make  an  enlarged  drawing  of  the  side  of  the  head,  showing  all 
the  parts. 

Exercise  4.  Remove  the  head  and  notice  the  occipital  foramen,  or  the 
large  opening  by  which  the  cavity  of  the  head  communicates  with  that  of  the 
neck  and  thorax. 


Section  II.    Mouth-Parts  of  Locusts 

Material.  In  order  to  effectively  study  the  mouth-parts  of  the  locust  each 
student  should  be  provided  with  prepared  slides  as  well  as  with  the  alcoholic 
specimens.  As  the  parts  are  removed  for  study  they  should  be  mounted  on 
glass  slides  in  a  glycerin  solution,  and  may  then  be  compared  with  the  pre- 
pared mounts.  The  parts  may  be  removed  by  grasping  them  at  their  attachment 
with  a  pair  of  stout  forceps  and  pulling  them  back  at  right  angles  to  their 
attachment. 

1.  Labrum.  The  labrum,  or  upper  lip,  is  a  flaplike  piece  at- 
tached to  the  lower  edge  of  the  clypeus.  The  free  edge  is  deeply 
notched  on  the  median  line. 


278  ELEMENTARY  ENTOMOLOGY 

2.  Mandibles.  These  lie  directly  beneath  the  labrum  and  con- 
sist of  a  pair  of. short,  thick  pieces.  The  inner  edge  is  somewhat 
flattened  and  provided  with  a  number  of  toothlike  projections 
which  form  the  grinding  surface  of  the  mandibles. 

3.  Maxillae.  These  are  the  second  pair  of  jaws  ;  they  lie  directly 
beneath  the  mandibles  and  are  much  more  complicated  in  struc- 
ture. After  they  have  been  removed  and  mounted  in  glycerin, 
the  following  parts  can  be  distinguished  : 

a.  The  cardo.  This  forms  the  attachment  or  basal  piece  of  the 
maxilla,  and  is  triangular  in  shape. 

b.  Tiie  stipes.  This  is  a  quadrangular-shaped  segment  forming 
the  central  part  of  the  maxilla.  One  side  is  attached  to  the  cardo, 
and  two  of  the  other  sides  form  the  attachment  for  the  remaining 
structures. 

c.  The  lacinia.  This  is  attached  to  the  inner  edge  of  the 
stipes,  and  is  a  long,  curved  piece  terminating  in  a  row  of  sharp 
teeth. 

d.  TJie  galea.  This  portion  of  the  maxilla  articulates  with  the 
stipes  on  its  outer  edge,  just  below  the  attachment  of  the  lacinia. 
It  closely  resembles  this  latter  structure,  except  that  the  end  is 
rounded  instead  of  being  toothed. 

e.  The  maxillary  palpcs.  These  arise  from  a  basal  portion 
known  as  the  palpifer,  which  articulates  with  the  stipes  between 
the  attachment  of  the  galea  and  the  cardo.  The  palpae  consist  of 
five  long,  slender  segments,  and,  like  the  antennae,  are  sensory  in 
function. 

4.  Labium.  The  labium,  or  under  lip,  forms  the  under  part  of 
the  mouth  and,  together  with  the  upper  lip,  almost  incloses  the 
mandibles  and  maxillae.  The  labium  is  a  complicated  structure 
made  up  of  the  following  parts  : 

a.  The  submentimi.  This  forms  the  attachment  to  the  epicra- 
nium  and  is  a  crescent-shaped  piece.  It  is  also  joined  to  the 
membrane  which  connects  the  head  with  the  thorax. 

b.  TJie  inentiLiii.  This  is  the  central  portion  of  the  labium,  and 
is  joined  to  the  distal  margin  of  the  submentum. 

c.  TJie  ligula.  The  ligula  consists  of  two  large,  movable  flaps 
attached  to  the  distal,  or  outer,  edge  of  the  mentum,  and  forms 
the  terminal,  central  portion  of  the  labium. 


THK  EXTERNAL  ANATOMY  OE  THE  LOCUST      279 

d.  The  labial  palpcc.  These  resemble  the  maxillary  palpae,  but 
consist  of  only  four  segments,  which  are  attached  to  the  palpifers. 
These  are  located  on  either  side  of  the  mcntum,  below  the  attach- 
ment of  the  ligula. 

5.  Hypopharynx.  The  hypopharynx,  or  tongue,  is  located  on 
the  floor  of  the  mouth,  between  the  maxillae.  It  is  diamond-shaped 
when  viewed  from  above,  and  is  covered  with  numerous  small 
taste  setae. 

Exercise  5.  Make  a  careful  drawing  of  the  mouth-parts,  showing  all  of  the 
above-named  structures. 

Section  III.    The  Thorax 

Material.  Each  student  should  be  provided  with  both  alcoholic  and  dry  speci- 
mens, and  should  remove  the  wings  and  legs  from  one  side  of  the  body  only. 

1.  Divisions  of  the  thorax.  As  has  already  been  noted,  the 
thorax  is  divided  into  three  segments,  known  as  the  prothorax, 
mesothorax,  and  metathorax. 

2.  Prothorax.  This  is  the  segment  to  which  the  head  is  attached, 
and  may  be  divided  into  two  regions,  —  a  dorsal  region  known  as 
the  pronotum,  and  a  ventral  region  known  as  the  sternum. 

a.  The  pronotum.  This  is  a  bonnetlike  piece  extending  over 
the  dorsal  and  lateral  region  of  the  prothorax.  It  is  made  up  of 
a  fusion  of  four  plates,  which  are  indicated  by  the  transverse  sutures. 
Anteriorly  there  is  an  opening  corresponding  to  the  occipital  fora- 
men of  the  epicranium. 

b.  TJic  stcrniim.  The  ventral  side,  or  sternum,  of  the  prothorax 
is  also  made  up  of  separate  plates,  or  sclerites.  The  anterior  sclerite 
bears  a  spine  on  the  median  line. 

c.  The  prothoracic  legs.  These  arise  from  the  ventral,  lateral 
region  of  the  prothorax.    Their  structure  will  be  noted  later. 

3.  Mesothorax  and  metathorax.  The  sclerites  of  these  two 
segments  are  very  intimately  associated,  and  their  structure  will  be 
discussed  together.  The  mesothorax  is  joined  to  the  prothorax  by 
a  membrane  which  permits  of  more  or  less  movement.  Posteriorly 
the  metathorax  is  joined  immovably  with  the  first  abdominal  seg- 
ment. The  hiesothorax  and  metathorax  form  a  strong,  boxlike  struc- 
ture for  the  support  of  the  wing  and  leg  muscles.    Like  the  prothorax 


28o         ELEMENTARY  ENTOMOLOGY 

these  segments  are  made  up  of  separate  plates,  held  together  by 
a  tough,  connecting  membrane.  These  plates  may,  however,  be 
divided  into  three  groups :  the  tergum,  or  dorsal  region ;  the 
sternum,  or  ventral  region  ;  and  the  pleuron,  or  lateral  region.  On 
the  dorsal  and  ventral  regions  of  the  body  the  sutures  separating  the 
mesothorax  from  the  metathorax  are  not  very  distinct.  On  the  sides 
of  the  body,  however,  there  is  a  very  distinct  line,  or  suture,  running 
from  the  posterior  border  of  the  attachment  of  the  second  pair 
of  legs  toward  the  dorsal  part  of  the  body.  This  suture  divides 
the  mesothorax  from  the  metathorax.  The  pleura  of  each  of  the 
posterior  thoracic  segments  are  again  divided  by  transverse  sutures, 
so  that  each  pleuron  consists  of  two  sclerites. 

a.  The  legs.  The  mesothoracic  and  metathoracic  legs  arise  from 
the  lower  posterior  border  of  the  pleura  of  their  respective  seg- 
ments, and  are  joined  to  the  thorax  by  a  tough,  elastic  membrane, 

b.  The  wings.  The  wings  have  a  more  anterior  origin  in  respect 
to  their  thoracic  segments  than  do  the  legs.  Each  pair  arises  at 
the  union  of  the  pleura  and  tergum. 

c.  The  spij-aeles.  The  spiracles,  or  openings  of  the  respiratory 
system,  consist  of  two  pair  6i  liplike  structures  situated  on  either 
side  of  the  bqdy  on  the  anterior  margin  of  the  pleural  plates.  The 
mesothoracic  spiracle  is  concealed  by  the  posterior  edge  of  the 
pronotum.  The  metathoracic  spiracle  is  located  just  dorsal  to 
the  mesothoracic  leg,  near  the  suture  separating  the  two  segments. 
There  is  another  spiracle  just  dorsal  to  the  attachment  of  the  meta- 
thoracic leg,  but  this  belongs  to  the  first  abdominal  segment. 

Exercise  6,  Make  a  full-page  drawing  of  a  side  view  of  the  thorax  of  a 
locust  with  the  wings  and  legs  removed,  showing  all  of  the  parts  noted  above. 

Section  IV.   The  Thoracic  AppENDACiES 

Material.  With  a  pair  of  fine-pointed  scissors  remove  the  legs  from  one 
side  of  the  body  of  the  locust  and  arrange  them  on  a  piece  of  white  paper  in 
their  regular  order.  Also  remove  the  wing  and  wing-cover  (mesothoracic  wing) 
from  one  side  and  pin  to  a  thin  sheet  of  cork,  spreading  the  wing  to  its  full 
dimension. 

1.  Legs.  Make  a  comparative  study  of  the  legs,  which  will  be 
found  to  consist  of  the  following  segments  : 


THE  EXTERNAL  ANATOMY  OF  THE   LOCUST      28 1 

a.  TJic  coxa.  This  is  the  first  segment,  and  is  attached  to  the 
thorax  by  a  tough,  elastic  membrane.  It  is  short,  almost  globular, 
and  is  more  distinct  on  the  prothoracic  legs  than  on  the  other  two. 

b.  TJic  trocJiaiitcr.  This  is  the  second  segment,  and  is  consid- 
erably shorter  than  the  coxa,  and  partially  or  entirely  fused  with  the 
next  segment.  It  is  hard  to  distinguish  except  in  the  first  pair 
of  legs. 

c.  The  fcj/uir.  lliis  is  the  third  and  largest  segment  of  the  leg, 
and  in  the  case  of  the  metathoracic  leg  contains  the  muscles  used 
in  jumping. 

d.  The  tibia.  This  is  the  fourth  segment,  and  is  much  more 
slender  than  the  femur,  although  about  equaling  it  in  length. 

e.  77ie  tarstts.  This  is  the  last  division,  and  is  made  up  of  three 
short  segments  freely  articulating  with  each  other.  These  seg- 
ments bear  a  series  of  pads,  which  terminate  on  the  last  one  in  a 
large,  suckerlike  disk  known  as  the  pulvillus.  On  each  side  of  the 
pulvillus  is  a  pair  of  claws,  the  ungues. 

Exercise  7.  Make  drawings  of  the  first  and  third  thoracic  legs,  showing  all 
the  parts. 

2.  Wing-covers.  The  wing-covers  are  leathery  in  texture  and 
do  not  fold  fanlike  over  the  abdomen,  as  do  the  two  wings.  They 
are  strengthened  by  numerous  veins  and  cross  veins. 

Exercise  8.  Make  an  enlarged  drawing  of  a  wing-cover,  noting  the  arrange- 
ment and  number  of  the  veins  and  cross  veins ;  also  note  the  attachment  to 
the  mesothorax. 

3.  Wings.  These  are  sometimes  called  the  second,  or  meta- 
thoracic, wings.  They  are  membranous  in  texture  and  fold  fanlike 
when  not  in  use.  They  are  also  strengthened  by  numerous  veins 
and  cross  veins,  as  are  the  wing-covers. 

Exercise  9.  Make  an  enlarged  drawing  of  a  wing,  showing  the  arrangement 
of  the  veins,  method  of  folding,  attachment,  etc. 


282  ELEMENTARY  ENTOMOLOGY 

Section  V.    The  Abdomen 

Material.  Each  student  should  be  provided  with  one  alcoholic  specimen 
each  of  the  male  and  the  female  locust.  The  remains  of  the  specimens  used  in 
previous  sections  will  be  sufficient. 

1.  Abdomen  of  the  male.  The  abdomen  of  the  male  locust  con- 
sists of  eleven  segments  ;  only  seven  of  these,  however,  are  complete. 

a.  The  first  abdominal  segmejtt.  This  is  made  up  of  a  curved, 
dorsal  shield,  the  tergum,  which  terminates  just  above  the  attach- 
ment of  the  third  pair  of  legs.  This  piece  partially  surrounds  the 
tympanic  membrane,  or  ear,  which  is  a  large,  crescent-shaped  area 
covered  with  a  semitransparent  membrane.  Between  the  ear  and 
the  attachment  of  the  legs  are  the  spiracles,  which  have  already 
been  noted.  The  ventral  part  of  the  first  segment,  the  sternum, 
is  not  attached  to  the  tergum,  owing  to  the  large  size  of  the  attach- 
ment of  the  legs.    The  pleura  are  entirely  absent. 

b.  The  second  to  eighth  abdominal  segments.  These  are  all  quite 
similar,  consisting  of  a  dorsal  tergum,  which  extends  laterally  to 
near  the  ventral  part  of  the  body,  where  it  joins  the  sternum. 
The  pleura,  or  side  pieces,  noted  in  connection  with  the  thorax, 
have  been  inseparably  fused  to  the  tergum.  One  pair  of  spiracles 
is  located  at  the  anterior  margin  of  each  segment  near  the  union 
of  the  sternum  and  tergum. 

c.  Segments  nine  and  ten.  The  terga  of  these  two  segments 
are  partially  fused  together,  the  union  of  the  two  being  indicated 
by  the  presence  of  a  transverse  suture.  The  sterna  of  these  two 
segments  are  entirely  fused  and  much  modified,  forming  a  broad, 
platelike  piece. 

d.  Segment  eleven.  This  is  represented  only  by  the  tergum, 
which  forms  the  terminal,  dorsal,  shield-shaped  piece. 

e.  TJie  cerci.  These  are  a  pair  of  plates  attached  to  the  lateral, 
posterior  border  of  the  tenth  segment,  and  extend  back  past  the 
end  of  the  eleventh  tergum. 

f.  The  snbgenital plate.  This  is  attached  to  the  ninth  sternum 
and  forms  the  most  posterior  ventral  plate  of  the  body. 

g.  The  podical  plates.  These  lie  directly  beneath  the  cerci  and 
ventral  to  the  eleventh  tergum.  The  anus  opens  between  these 
plates,  and  the  genital  chamber  lies  directly  below  them. 


THE  EXTERNAL  ANATOMY  OF  THE  LOCUST      283 

Exercise  10.  Make  an  enlarged  drawing  of  the  side  view  of  the  abdomen  of 
the  male  locust,  showing  all  of  the  above  parts. 

2.  Abdomen  of  the  female.  The  abdomen  of  the  female  from  the 
first  to  the  seventh  segment  is  nearly  the  same  as  in  the  male. 

a.  Segment  eigJit.  This  segment  resembles  the  other  segments, 
except  that  the  sternum  is  nearly  twice  as  long,  and  is  known  as 
the  subgenital  plate. 

b.  Segments  nine,  ten,  and  eleven.  These  are  essentially  like 
those  of  the  male,  the  tergum  of  nine  and  ten  being  partially  fused, 
and  tergum  eleven  forming  the  terminal,  dorsal  shield. 

c.  The  eeiri  and  podieal  plates.  These  plates  are  similar  to 
those  in  the  male,  except  that  the  podieal  plates  are  much  more 
prominent. 

d.  TJie  ovipositor.  The  ovipositor  consists  of  three  pairs  of 
movable  plates.  The  dorsal  pair  lie  just  ventral  to  the  eleventh 
tergum  and  are  long,  lance-shaped  pieces  with  hard,  pointed  tips. 
The  ventral  pair  arises  just  dorsal  to  the  eighth  sternum  and 
resembles  the  dorsal  pair.  When  these  four  pieces  are  brought 
together,  their  points  are  in  contact,  forming  a  sharp  organ  b}' 
means  of  which  the  female  bores  the  holes  in  the  ground  in  which 
to  deposit  her  eggs.  The  third  set  of  plates  are  known  as  the  egg 
guides.  These  are  much  smaller  and  are  located  median  to  the 
plates  of  the  true  ovipositor. 

Exercise  11.  Make  a  drawing  of  the  side  view  of  the  last  five  segments  of 
the  female  locust. 


CHAPTER  XVII 

A  COMPARISON  OF  THE  DIFFERENT  TYPES  OF  ARTHROPODA 

Section  VI.    Comparison  of  Insects  and  Crustaceans 
(Types,  Locust  and  Crayfish) 

Material.  Alcoholic  specimens  of  both  crayfish  and  locusts  should  be  pro- 
vided, although  the  student  by  this  time  should  be  familiar  with  the  structure 
of  the  locust.  The  lobster  is  much  larger  and  easier  to  work  than  the  crayfish, 
and  instructions  here  given  will  apply  to  either.  Both  the  lobster  and  the  crayfish 
may  be  obtained  from  any  of  the  natural-history  supply  companies.  Crayfish 
may  be  collected  in  many  sections  of  the  country  from  streams  and  ponds, 
and  should  be  preserved  in  the  same  manner  as  recommended  for  the  locust. 
Material  for  Exercise  17  (the  sow-bug)  can  be  obtained  in  abundance  under 
boards  and  stones  and  in  other  damp  locations.  It  may  be  preserved  in 
alcohol. 

Exercise  12.  Comparison  of  the  anatomy  of  the  crayfish  atid  the  locust. 
With  the  two  specimens  at  hand,  write  out  a  careful  comparison  of  the  following 
points : 

1.  Nature  of  the  body  covering. 

2.  General  divisions  of  the  body.  (A  fusion  of  the  head  and  thorax  is  known 
as  the  cephalothorax.) 

Exercise  13.  The  head  and  head  appendages.  Remove  the  appendages 
from  one  side  of  the  crayfish,  beginning  with  the  first  appendage  anterior  to 
the  first  walking  leg.  These  may  be  removed  by  grasping  them  near  their 
attachment  with  a  pair  of  strong  forceps,  and  pulling  them  backwards  toward 
the  posterior  end  of  the  body.  As  each  one  is  removed,  it  should  be  laid  on  a 
piece  of  wet  blotting  paper  in  regular  order.  The  appendages  of  the  crayfish 
are  numbered  from  the  anterior  to  the  posterior  end  of  the  body.  The  head 
appendages  are  as  follows  : 

1 .  The  antennule,  consisting  of  a  basal  piece  and  two  long,  slender  filaments. 

2.  The  antenna,  consisting  of  a  basal  piece,  one  long,  slender  filament, 
known  as  the  endopodite,  and  a  short,  platelike  projection,  known  as  the 
exopodite. 

3.  The  mandibles. 

4.  5.  The  first  and  second  maxillae.  The  above  include  all  the  head  append- 
ages. Write  out  a  careful  comparison  of  these  appendages  and  corresponding 
appendages  in  the  locust.  Also  with  a  hand  lens  make  a  comparative  study 
of  the  eyes. 

284 


THE-  DIFFERENT  TYPES   OF  ARTHROPODA        285 

Exercise  14.  ./  coiiiparison  of  the  llioracit  appendages.  Appendages  6,  7, 
and  8  of  the  thorax  are  known  as  the  first,  second,  and  third  inaxillipeds,  and 
the  appendages  from  9-13  are  the  walking  appendages.  Write  out  a  comparison 
of  the  thoracic  appendages,  noting  the  number,  segmentation,  etc. 

Exercise  15.  A  comparative  study  of  the  abdomens  of  the  crayfish  and 
locust.  Appendages  14-20  of  the  crayfish  are  known  as  the  swimmerets. 
Compare  these  with  the  more  anterior  appendages  of  the  crayfish.  Also  write 
out  a  careful  comparison  of  the  segmentation  of  the  abdomens  of  the  crayfish 
and  locust. 

Exercise  16.  Make  a  drawing  of  the  side  view  of  the  crayfish,  naming  the 
different  appendages  and  divisions  of  the  body. 

Exercise  17.    Make  drawings  of  appendages  2,  10,  and  16. 

Exercise  18.  Comparison  of  the  locust  and  sow-bug.  Write  out  a  careful 
comparison  of  these  two  forms,  noting  : 

1.  The  nature  of  the  body  covering. 

2.  The  general  divisions  and  segmentation  of  the  body. 

3.  The  nature  of  the  appendages. 

4.  The  number  and  position  of  the  appendages. 

Exercise  19.  Make  a  drawing  of  the  ventral  view  of  the  sow-bug,  showing 
the  number,  position,  and  arrangement  of  the  appendages. 


Section  VII.    Comparison  of  Insects  and  Myriapoda 
(Types,  Locust  and  Centipede) 

Material.  Centipedes  are  flattened,  wormlike  animals  living  under  logs,  stones, 
and  other  damp  localities.  They  are  quite  common  in  most  places,  and  may  be 
collected  and  preserved  in  75  per  cent  alcohol.  Large  specimens  may  usually 
be  supplied  by  most  of  the  natural-history  supply  houses. 

Exercise  20.  Write  out  a  detailed  comparison  of  a  centipede  and  locust,  noting 
the  following  points : 

1 .  The  general  divisions  of  the  body. 

2.  The  nature  of  body  covering. 

3.  The  segmentation  of  the  body. 

4.  The  eyes  and  antennae. 

5.  The  mouth-parts. 

6.  The  legs,  number  of  their  segments,  etc. 
Exercise  21.    Make  a  drawing  of  the  dorsal  view  of  the  head. 
Exercise  22.    Make  a  drawing  of  a  ventral  view  of  the  head. 


2  86  ELEMENTARY  ENTOMOLOGY 

Section  VIIL    Comparison  of  Insects  and  Arachnida 
(TvpES,  Spider  {Argiopc)  and  Locust) 

Material.  When  possible,  the  ladder-spider  should  be  collected  for  this  work, 
as  it  is  large,  brilliantly  colored,  and  can  usually  be  collected  in  large  numbers 
in  the  fall. 

Exercise  23.    Write  out  a  careful  comparison  of  the  following  parts: 

1.  The  cov'ering  of  the  body  and  segmentation. 

2.  The  general  divisions  of  the  body. 

3.  The  eyes  (located  on  the  anterior  portion  of  the  cephalothorax),  their 
number,  arrangement,  etc. 

4.  The  mouth-parts,  consisting  of  the  mandibles,  with  terminal  fang,  maxillae, 
hypopharynx,  and  a  rudimentary  labium. 

5.  The  legs,  number,  number  of  segments,  etc. 

6.  The  abdomen,  including  the  following  structures  : 

a.  The  opening  of  the  book-lungs,  which  lie  on  either  side  of  the  me- 

dian line  at  the  anterior  end  of  the  abdomen  and  are  respiratory 
in  function. 

b.  The  genital  opening,  situated  in  the  female  on  a  prominent  median 

tubercle  located  between  the  book-lungs. 

c.  The  spinnerets,  consisting  of  six  papillae  at  the  posterior  end  of  the 

body. 
Exercise  24.    Make  a  drawing  of  a  dorsal  view  of  the  spider. 
Exercise  25.    Make  a  drawing  of  the  mandibles  and  maxillae  of  the  spider. 


CHAPTER   XVIII 

A  COMPARISON   OF   DIFFERENT   TYPES   OF  INSECTS;   STRUCTURE 
OF  THE  BEE,   FLY,   AND  BEETLE 

Section  IX.    Anatomy  of  the  Honey-Bee  (Second  Type  of 
THE  Class  Insecta) 

Material.  The  ordinary  honey-bee  can  be  easily  collected  for  this  work,  and 
should  be  in  as  fresh  a  condition  as  possible.  While  alcoholic  specimens  will 
do,  it  is  much  better  to  furnish  the  students  with  fresh  material,  or  to  dry  the 
specimens  and  place  them  in  a  moist  chamber  about  two  hours  before  using. 
It  is  almost  imperative  that  the  students  be  supplied  with  prepared  slides  of 
the  legs  to  supplement  the  dry  material.  As  this  section's  work  will  not  deal 
with  the  mouth-parts,  prepared  slides  of  these  will  not  be  needed  until  later. 

1.  General  anatomy  of  the  honey-bee.  The  bee  furnishes  an  ex- 
cellent example  of  the  specialization  of  insects,  all  of  the  parts  being 
modified  for  a  special  purpose.  This  laboratory  section's  work  is 
intended  to  give  the  student  an  idea  of  these  modifications,  with 
the  exception  of  the  mouth-parts,  which  will  be  studied  later.  The 
plan  of  structure  does  not  differ  much  from  that  of  the  locust ;  the 
student,  however,  should  notice  the  following  points  : 

Exercise  26.    Write  out  a  careful  comparison  of  the  bee  and  locust  as  follows  : 

1.  The  nature  of  the  body  covering. 

2.  The  segmentation  of  the  body. 

3.  The  divisions  of  the  body. 

4.  The  number  and  position  of  the  appendages. 

5.  The  structure  of  the  head  (except  the  mouth-parts).  Note  the  compound 
eyes,  ocelli,  and  antennas. 

2.  Modifications  of  the  prothoracic  leg.  Carefully  remove  the 
prothoracic  legs  and  mount  in  the  glycerin  solution.  Compare 
with  the  prepared  slides  and  notice  the  following  points  (the  gen- 
eral divisions  of  the  leg  are  the  same  as  those  of  the  locust) : 

a.  TIic  coxa.  This  basal  piece  is  a  rather  large,  triangular  seg- 
ment attached  to  the  prothorax. 

287 


288         ELEMENTARY  ENTOMOLOGY 

b.  TJic  trocJiajitcr.  This  is  proportionally  larger  than  in  the 
locust ;  aside  from  this  it  shows  no  special  modifications. 

c.  TJie  fcimir.  This  is  a  large,  club-shaped  joint  covered  with 
long  hairs. 

d.  The  tibia.  This  segment  is  smaller  than  the  preceding  and 
is  provided  with  a  spine  at  the  lower  end. 

e.  The  tarsus.  The  tarsus  consists  of  five  segments,  the  first 
being  nearly  as  large  as  the  tibia.  It  is  provided  with  a  notch,  near 
its  attachment  to  the  tibia,  which,  together  with  the  spine  on  the 
latter  segment,  forms  the  antenna  cleaner. 

Notice  also  the  bilobed  claws  on  the  end  of  the  tarsus,  together 
with  the  median,  flaplike  structure  known  as  the  empodium.  This 
secretes  a  slicky  substance,  which  enables  the  bee  to  walk  on  a 
smooth  surface. 

Exercise  27.  Make  an  enlarged  drawing  of  a  prothoracic  leg,  showing  the 
segmentation,  antenna  cleaner,  claws,  etc. 

3.  Mesothoracic  leg.  The  mesothoracic  leg  differs  but  slightly 
from  the  prothoracic  leg,  except  that  the  antenna  cleaner  is  absent 
and  that  on  the  inner  side  of  the  tibia  there  is  a  spur  used  in  loosen- 
ing the  pollen  from  flowers. 

Exercise  28.  Make  drawing  of  the  inner  side  of  the  tibia  and  tarsus  of  the 
mesothoracic  leg,  showing  the  spine. 

4.  Metathoracic  leg.  This  resembles  the  prothoracic  leg,  with 
the  following  modifications  : 

a.  T]ic  pollen-basket.  The  outer  surface  of  the  tibia  of  the  third 
thoracic  leg  is  smooth  and  surrounded  with  a  row  of  long,  incurved 
hairs.  This  is  known  as  the  pollen-basket,  and  is  used  in  carr)dng 
the  pollen  to  the  hive. 

b.  TJie  ivax  piiieeis.  Between  the  end  of  the  tibia  and  the  tarsus 
is  a  pincerlike  structure  consisting  of  a  row  of  thick,  flattened  spines 
on  the  edge  of  the  tibia,  which  come  in  contact  with  the  smooth 
edge  of  the  tarsus.  These  wax  pincers  are  supposed  to  be  used  in  re- 
moving the  plates  of  wax  from  the  abdomen,  where  they  are  secreted. 

c.  TJie  pollen  eomb.  This  structure  is  located  on  the  inner  sur- 
face of  the  flat,  basal  segment  of  the  tarsus,  and  consists  of  nine 
parallel  rows  of  bristles,  which  are  used  in  combing  the  pollen  from 
the  body,  where  it  collects  while  the  bee  is  gathering  nectar. 


COMPARISON  OF  DIFFERENT  INSECTS  289 

Exercise  29.    Make  a  drawing  of  the  inner  surface  of  tlie  third  thoracic  leg. 

Exercise  30.    Make  a  drawing  of  the  outer  surface  of  the  third  thoracic  leg. 

Exercise  31.  Examine  the  wings  of  the  bee  under  the  compound  micro- 
scope and  make  a  drawing  showing  the  fine  hooks  and  groove  by  means  of 
which  the  wings  ai'e  locked  together  during  flight.  Also  notice  the  arrangement 
of  the  veins. 


Section  X.  Comparison  of  the  Flv  with  the  Loclst  and  Bee 

Material.  Probably  the  best  material  for  the  study  of  the  anatomy  of  the 
Diptera  is  some  of  the  large  horse-flies,  like  Taba)iiis  atra/us,  although  these 
may  be  hard  to  secure  in  sufficient  numbers.  If  these  cannot  be  secured,  any 
of  the  smaller,  more  abundant  species  will  suffice.  The  material  may  be  pre- 
served in  75  per  cent  alcohol,  or  dried,  the  latter  method  probably  being  pref- 
erable for  a  study  of  the  external  parts ;  the  specimens  should,  however,  be 
placed  in  a  moist  chamber  at  least  twenty-four  hours  before  they  are  wanted 
for  use. 

Exercise  32.  Write  out  a  careful  comparative  description  of  the  external 
anatomy  of  the  fl}\  comparing  it  with  the  locust  and  the  bee,  and  noting  the 
following  points  of  structure  : 

1 .  The  divisions  of  the  body,  the  body  covering,  and  the  segmentation. 

2.  The  head  and  its  appendages,  with  the  exception  of  the  mouth-parts. 

3.  The  thorax  and  thoracic  appendages. 

4.  The  abdomen  and  its  segmentation. 

Exercise  33.  Make  a  drawing  of  the  wing  of  a  fly,  comparing  it  with  the  text 
figure. 

Section   XI.    Comparison    oi'   a   Beetle  with    the    Locust 

AND  Bee 

Material.  Almost  any  of  the  larger  beetles  will  serve  for  this  work,  although 
the  May-beetle  will  probably  be  the  easiest  to  secure.  These  should  be  pre- 
served in  the  alcohol-glycerin  solution. 

Exercise  34.  Write  out  a  comparison  of  the  beetle  with  the  locust  and  bee, 
noting : 

1 .  The  nature  of  the  body  covering,  the  segmentation,  and  the  divisions  of 
the  body. 

2.  The  head,  including  the  eyes  and  antennae. 

(If  time  permits,  the  mouth-parts  of  the  beetle  might  profitably  be  dissected 
and  compared  with  those  of  the  locust.) 

3.  The  thorax,  including  the  wings  and  wing-covers,  especially  noting  the 
modification  of  the  wing-covers. 

4.  The  abdomen,  the  number  of  segments,  etc. 

Exercise  35.  Make  a  drawing  of  the  antennas,  wings,  and  wing-covers  of 
the  beetle. 


CHAPTER   XIX 
THE  INTERNAL  ANATOMY  OF  THE  LOCUST 

Section   XII 

MateriaL  Fresh  material  will  be  found  the  most  satisfactor}'  for  this  work, 
the  specimens  being  placed  in  85  per  cent  alcohol  for  about  an  hour  before 
being  used.  If  fresh  material  is  not  available,  alcoholic  specimens  that  have  been 
previously  soaked  in  warm  water  for  a  short  time  will  work  very  satisfactorily. 
After  removing  the  wings  and  legs  from  the  right  side  of  the  locust,  make  a 
longitudinal,  dorsal  incision  to  the  right  of  the  median,  dorsal  line,  and  the 
entire  length  of  the  body.  Make  a  similar  longitudinal  ventral  incision  to  the 
right  of  the  midventral  line.  Remove  carefully  the  right  side  of  the  chitinous 
covering,  exposing  all  of  the  internal  organs,  of  which  the  following  systems 
should  be  studied : 

1.  Digestive  system.  The  digestive  system  occupies  the  greater 
part  of  the  thoracic  and  the  ventral  part  of  the  abdominal  cavity. 
It  is  essentially  a  continuous  tube,  divided  into  the  following  re- 
gions, each  with  a  particular  function  to  perform. 

a.  TJic  esophagus.  This  is  a  cylindrical  tube,  with  tough,  mus- 
cular walls.  It  runs  from  the  mouth,  opening  dorsally  to  a  point 
opposite  the  foramenal  aperture,  where  it  bends  at  right  angles 
and  enters  the  thorax. 

b.  TJie  crop.  This  is  an  enlargement  of  the  esophagus  and,  be- 
ginning in  the  mesothorax,  runs  to  the  abdomen,  almost  filling  the 
mesothoracic  and  metathoracic  cavities, 

c.  The  giaaard  {provejitriciilus).  This  is  the  next  division  (not 
found  in  the  genus  Aeridiiun) .  The  walls  are  thick  and  muscular, 
and  on  the  inside  are  lined  with  a  series  of  chitinous  plates  which 
are  used  in  completing  the  mastication  of  the  food, 

d.  The  stomach  (ventrietdiis).  This  division  is  separated  from 
the  gizzard  by  a  slight  constriction.  It  is  approximately  the  same 
diameter  as  the  gizzard  and  extends  from  the  first  to  the  seventh 
segment  of  the  abdomen, 

e.  TJie  large  intestine.  This  is  of  somewhat  smaller  diameter 
than  the  stomach  and  runs  from  the  seventh  to  the  tenth  segment, 

290 


THE  INTERNAL  ANATOMY  OF  THE  LOCUST       29 1 

f ,  TJic  small  intestine.  The  small  intestine  is  a  short,  muscular 
tube  running  from  the  end  of  the  large  intestine  toward  the  dorsal 
part  of  the  body  and  ending  in  segment  eleven, 

g.  The  rectuui.  The  rectum  is  a  short,  muscular  enlargement 
in  segment  eleven  and  ends  in  the  anal  opening. 

2.  Accessory  organs  of  digestion.  In  connection  with  the  ali- 
mentary tract  are  a  certain  number  of  glands  or  glandular  structures 
which  either  aid  in  the  digestion  of  the  food  or  assist  in  eliminating 
the  waste  products. 

a.  TJie  salivary  glands.  These  are  small,  white  glands  located 
on  either  side  of  the  esophagus  in  the  thorax.  They  open  out  into 
two  main  ducts  which  lead  to  the  mouth. 

b.  The  gastfie  cccca.  The  gastric  caeca  consist  of  a  set  of  eight 
double,  cone-shaped  pouches  which  open  at  the  union  of  the  crop 
and  stomach.  They  form  a  complete  belt  around  the  alimentary 
tract  at  this  point  and  secrete  a  fluid  which  aids  in  digestion. 

c.  The  Malpigiiian  tubules.  The  Malpighian  tubules  are  a  sys- 
tem of  ver}'  fine,  hairlike  tubes  which  arise  from  the  most  anterior 
end  of  the  large  intestine.  Their  function  is  excretory,  similar  to 
that  of  the  kidneys. 

3.  Reproductive  system.  The  ease  with  which  the  organs  of 
this  system  may  be  distinguished  depends  considerably  on  the  sex 
and  the  time  of  year  at  which  the  specimens  were  collected. 

a.  Female  reproduetive  organs.  In  the  fall,  just  before  the  eggs 
are  deposited,  the  entire  abdomen  of  the  female  is  filled  with  a 
yellow,  coarsely  granular  organ  known  as  the  ovary.  There  are  a 
pair  of  these,  one  located  on  either  side  of  the  body.  Running 
from  the  posterior  end  of  the  ovary  are  two  small  tubes  called  the 
oviducts,  which  unite  near  the  posterior  end  of  the  body  to  form 
the  vagina.  This  opens  externally  upon  the  upper  surface  of  the 
subgenital  plate,  between  the  ovipositor.  On  a  median  line  slightly 
dorsal  to  the  ^g^  guides  there  is  a  second  opening,  which  communi- 
cates with  a  long,  slender  tube  ending  in  an  enlarged  pouch  known 
as  the  spermatheca.    This  entire  structure  is  very  difficult  to  locate. 

b.  Male  reproductive  organs.  The  general  arrangement  of  the 
male  reproductive  organs  is  quite  similar  to  that  of  the  female,  only 
much  smaller.  The  two  pair  of  testes  (corresponding  to  the  ovaries) 
lie  on  the  dorsal  side  of  the  stomach  and  are  inclosed  in  a  saclike 


2  92         ELEMENTARY  ENTOMOLOGY 

membrane.  Leading  from  the  testes  are  two  very  fine,  hairlike 
tubes  known  as  the  vas  deferens.  These  pass  down  to  the  ventral 
side  of  the  body  on  either  side  of  the  alimentary  tract  and  unite, 
forming  the  ejaculatory  duct,  which  opens  dorsally  to  the  subgenital 
plate.  Just  before  the  union  of  the  vas  deferens  they  are  joined 
on  either  side  by  a  number  of  fine  tubules  known  as  the  seminal 
vesicles,  the  function  of  which  is  to  store  up  the  products  of  the 
reproductive  glands. 

Exercise  36.  Make  a  careful  drawing  of  the  side  view  of  a  locust,  showing 
the  alimentary  tract,  accessory  organs  of  digestion,  and  either  the  male  or  the 
female  reproductive  system. 

4.  Nervous  system.  With  a  pair  of  fine  scissors  cut  the  alimen- 
tary tract  through  the  esophagus  and  small  intestine,  and  carefully 
remove,  together  with  the  reproductive  organs.  Great  care  must  be 
taken  to  not  injure  or  displace  any  of  the  other  organs.  Also  care- 
fully remove  the  right  side  of  the  chitinous  portion  of  the  head. 

The  nervous  system  consists  principally  of  a  supra-esophageal 
ganglion,  or  brain,  which  lies  dorsal  to  the  esophagus.  This  is  a  large, 
whitish  mass  of  nervous  tissue  and,  if  carefully  dissected,  can  be 
seen  to  be  directly  connected  with  the  compound  eyes.  Running 
on  either  side  of  the  esophagus  is  a  small,  white  nerve  cord  that 
unites  on  the  ventral  side,  forming  the  sub-esophageal  ganglion. 
Running  from  this  ganglion  toward  the  posterior  end  of  the  body 
is  the  ventral  nerve  cord.  If  carefully  examined,  this  will  be  found 
to  consist  of  two  parallel  white  cords  that  are  occasionally  united 
by  the  ventral  ganglia,  from  which  arise  numerous  lateral  nerves. 
These  ventral  ganglia  occur  in  the  following  segments,  —  the 
prothorax,  mesothorax,  metathorax,  and  abdominal  segments  two, 
three,  five,  six,  and  seven. 

5.  Muscular  system.  In  elementary  work  of  this  sort  no  attempt 
will  be  made  to  trace  out  the  different  sets  of  muscles,  but  the 
general  relation  of  the  different  muscles  to  the  segments  should  be 
noted.  In  the  mesothorax  and  metathorax  notice  the  large  wing  mus- 
cles ;  also  in  the  abdomen  notice  the  longitudinal  and  ventral  bands. 

6.  Respiratory  system.  The  respiratory  system  is  made  up  of 
tubes  known  as  trachea.  These  open  out  along  either  side  of  the 
body  ;  the  openings,  which  have  already  been  noted,  are  termed  the 


THE  INTERNAL  ANATOMY  OF  THE  LOCUST 


293 


spiracles.  Soon  after  entering  the  body  the  trachea  unite  to  form 
two  large  lateral  trunks.  T^rom  these,  dorsal  branches  are  given  off, 
which  unite,  forming  two  parallel  dorsal  trunks.  Running  off  from 
both  the  dorsal  and  lateral  trunks  are  smaller  branches,  which 
separate  into  extremely  minute  tubes  and  ramify  through  all  the 
tissues. 

Exercise  37.  If  fresh  specimens  are  at  hand,  mount  in  water  some  of  the 
fatty  tissue  surrounding  the  alimentary  tract,  and  examine  under  the  compound 
microscope.  The  trachea  will  be  seen  as  much-branched  silver-colored  tubes. 
Make  a  careful  drawing. 

Exercise  38.  Make  a  drawing  of  the  side  view  of  the  locust,  with  the  alimen- 
tary tract  and  reproductive  organs  removed,  showing  the  general  arrangement 
of  the  muscular,  tracheal,  and  nervous  systems. 

7.  Circulatory  system.  The  circulatory  system  consists  of  a 
dorsal,  median,  tubular  heart.  This  can  be  seen  in  fresh  specimens 
by  removing  the  dorsal  body  wall. 

Exercise  39.  In  order  to  observe  the  rhythmic  contraction  of  the  heart, 
obtain  living  larvae  of  mosquitoes,  dragon-flies,  or  Ma3'-flies.  Place  them  in 
water  on  a  slide  and  examine  under  the  microscope.    Draw. 


CHAPTER  XX 

MOUTH-PARTS  OF  INSECTS 

The  type  of  biting  mouth-parts  has  already  been  considered 
in  Chapter  XVI,  the  forms  here  considered  being  more  highly 
specialized. 

Section  XIII.    Sucking  Mouth-Parts  (Type,  Squash-Bug) 

Material.  Students  should  be  provided  with  prepared  slides  of  the  mouth- 
parts  of  the  squash-bug.  They  should  also  have  alcoholic  specimens,  as  the 
arrangement  of  the  parts  cannot  be  easily  distinguished  on  the  prepared  slides. 
Before  studying  the  prepared  slides  the  students  should  dissect  out  the  mouth- 
parts  of  an  alcoholic  specimen.  With  a  pair  of  sharp-pointed  scissors  cut  off 
the  ventral  part  of  the  head  and  place  it  in  a  thick  glycerin  solution,  consist- 
ing of  equal  parts  of  glycerin  and  alcohol.  Then,  under  the  lens  of  a  dissect- 
ing microscope,  pull  the  long  proboscis  apart,  noting  the  order  of  arrangement 
of  the  different  pieces. 

The  mouth-parts  of  the  squash-bug  consist  of  a  long,  jointed  beak  in  which 
are  found  four  long,  threadlike  setae.  They  should  be  compared  with  the 
mouth-parts  of  the  locust. 

1.  Labrum.  The  labrum,  or  upper  lip,  is  a  long,  triangular, 
sharply  pointed  piece,  with  slightly  serrated  edge,  and  fits  over 
the  groove  of  the  lower  lip. 

2.  Mandibles.  The  mandibles  are  a  pair  of  long,  hairlike  setae 
with  sharp-toothed  points.  They  adhere  very  closely  together,  and 
are  used  in  cutting  into  the  tissues  of  plants  in  order  to  induce 
a  flow  of  sap. 

3.  Maxillae.  These  closely  resemble  the  mandibles  and,  like 
them,  lock  together,  forming  a  lancelike  structure.  They  are  used 
in  piercing  plants,  the  same  as  the  mandibles. 

4.  Labium.  The  labium,  or  under  lip,  is  formed  into  a  long, 
partially  closed  tube„  in  which  lie  the  mandibles  and  maxillae.  It  is 
made  up  of  four  segments  of  about  equal  length. 

Exercise  40.  Make  a  careful  drawing  of  the  mouth-parts  of  the  squash-bug, 
showing  the  above  details. 

294 


MOUTH-PARTS  OF  INSECTS  295 

Section  XIV.    Specialized   Piercing  Mouth-Parts 
(Type,   Horse-fly) 

Material.  Specimens  of  any  of  the  common  horse-flies  (Tabaiais)  will  do 
for  this  work,  though  only  female  flies  can  be  used,  as  the  mandibles  are  lack- 
ing in  the  males.  The  two  sexes  may  be  distinguished  by  the  position  of  the 
eyes.  In  the  male  the  eyes  touch  for  a  greater  or  less  distance,  while  in  the 
female  there  is  a  narrow  space  between  the  eyes.  The  mouth-parts  are  quite 
conspicuous  and  should  be  removed  and  mounted  as  in  the  previous  section. 
Students  should  also  be  provided  with  prepared  slides.  A  comparison  should 
be  made  with  the  mouth-parts  already  studied.  The  mouth-parts  of  the  fly  are 
more  highly  specialized  than  those  of  the  squash-bug,  and  consist  of  a  number 
of  stylets,  or  flat,  pointed  pieces,  more  or  less  completely  inclosed  in  the  fleshy 
under  lip.    They  consist  of  the  following  parts : 

1.  Labrum.  The  labrum,  or  upper  lip,  is  the  uppermost  stylet, 
and  consists  of  a  flat,  unpaired  piece,  bluntly  tipped.  It  is  broader 
than  any  of  the  remaining  stylets. 

2.  Mandibles.  These  consist  of  a  pair  of  flat,  smooth,  sharply 
pointed  pieces  adapted  for  piercing. 

3.  Maxillae.  These  are  the  second  pair  of  stylets  and  are  under- 
neath the  mandibles,  which  they  very  closely  resemble.  The  max- 
illae are  narrower  than  the  mandibles,  are  less  strongly  chitinized, 
and  are, provided  with  palps,  which  are  attached  to  the  base  of  each 
maxilla.  The  palps  consist  of  two  segments  and  are  thick,  clublike 
structures  covered  with  very  fine  hairs. 

4.  Hypopharynx.  The  hypopharynx,  or  tongue,  is  a  slender, 
unpaired  piece  resembling  very  much  the  labrum,  but  is  narrower 
and  more  sharply  pointed.    It  lies  directly  underneath  the  maxillae. 

5.  Labium.  This  is  a  conspicuous,  proboscislike  structure, 
which  partially  incloses  the  other  mouth-parts.  At  the  end  of  the 
labium  is  a  large,  fleshy,  disklike  piece  called  the  labella.  It  con- 
sists of  two  lobes,  which  fit  closely  around  the  stylets  when  they 
are  being  used. 

Exercise  41.    Make  careful  drawings  of  the  above  mouth-parts. 


296  ELEMENTARY  ENTOMOLOGY 

Section  XV.    Sucking  Mouth-Parts 
(Type,   Butterfly) 

Material.  The  commonest  type,  and  one  of  the  best  for  this  work,  is  the 
monarch  butterfly  [Anosta  plexippus).  These  may  be  collected  and  dried  and 
the  scales  carefully  removed  from  the  head  with  a  stiff  camel's-hair  brush. 
Part  of  the  specimens  should  be  boiled  in  caustic  potash  (KOH)  and  the  head 
mounted  in  balsam.  The  remainder  of  the  specimens  should  be  placed  in  the 
moist  chamber  for  a  day  or  so  before  they  are  wanted.  The  mouth-parts  of  the 
Lepidoptera  are  greatly  modified,  and  only  careful  study  reveals  the  relation 
between  them  and  the  biting  mouth-parts  of  the  locust. 

1.  Labrum.  This  is  a  very  short,  quadrangular  piece,  ahnost  or 
entirely  indistinguishable  in  some  species,  as  it  is  immovably  joined 
to  the  clypeus. 

2.  Mandibles.  The  mandibles  are  almost  entirely  wanting  in  the 
monarch  butterfly,  although  they  are  represented  in  some  forms 
by  two  triangular  pieces  which  are  of  little  or  no  use  to  the  insect. 
In  some  of  the  moths  they  are  more  highly  developed. 

3.  Maxillae.  The  maxillae  are  the  most  conspicuous  part  of  the 
mouth,  the  two  together  forming  a  long,  coiled  sucking  tube  used 
in  drawing  up  nectar.  Each  maxilla  is  deeply  grooved  on  the 
inner  side,  the  two  fitting  together,  forming  a  complete  tube.  The 
maxillary  palps  are  wanting  in  this  form,  although  present  'in  some 
of  the  lower  forms. 

4.  Labium.  The  labium  consists  of  a  small,  triangular  flap 
almost  completely  fused  with  the  base  of  the  maxillae.  Extending 
out  from  either  side  of  the  labium  are  the  large  labial  palps,  which 
form  two  prominent,  plumelike  projections  from  either  side  of  the 
head.    They  are  three-jointed  and  covered  with  scales. 

Exercise  42.  Make  a  drawing  of  the  mouth-parts  of  the  monarch  butterfly, 
showing  the  above  in  detail. 


Section   XVI.    Sucking   and   Biting   Mouth-Parts 
(Type,  Honey-bee) 

Material.  The  honey-bees  for  this  section's  work  may  be  preserved  in  75 
per  cent  alcohol.  It  may  be  found  advantageous  to  substitute  the  bumble-bee, 
as  the  mouth-parts  are  larger  and  more  easily  dissected.  In  either  case  it  is 
desirable  that  the  students  be  provided  with  prepared  slides.    The  mouth-parts 


MOUTH-PARTS  OF  INSECTS 


297 


of  the  honey-bee  are  made  up  of  the  typical  number  of  parts,  but  are  adapted 
both  for  biting  and  sucking.  The  student  should  refer  to  the  other  types  of 
mouth-parts  already  studied. 

1.  Labrum.  This  consists  of  a  small,  rectangular  piece  attached 
to  the  clypeus,  and  resembles  closely  the  labrum  of  the  locust. 

2.  Mandibles.  These  are  hard,  well-developed  structures,  more 
elongated  than  in  the  locust,  and  are  devoid  of  teeth. 

3.  Maxillae.  The  maxillse  are  complicated  structures  and,  as  in 
the  locust,  consist  of  the  following  parts  : 

a.  TJie  cardo.  This  serves  as  the  attachment  to  the  epicranium 
and  is  an  elongated  piece. 

b.  TJic  stipes.  These  are  rather  thick,  club-shaped  pieces  strongly 
chitinized. 

c.  The  maxillary  palps.  These  are  short  and  almost  atrophied, 
located  at  the  distal,  outer  edge  of  the  stipes. 

d.  TJie  laeinia  galea.  These  two  structures  are  fused  together 
in  the  bee  and  form  a  pair  of  elongated  pieces  deeply  grooved  on  the 
inner  edge.  When  fitted  together,  they  form  a  partially  closed  tube 
more  or  less  completely  surrounding  the  parts  of  the  labium, 

4.  Labium.  The  labium,  or  under  lip,  is  even  more  modified 
than  the  maxillae,  and  consists  of  the  following  parts  : 

a.  TJie  subfuentiim.  This  is  a  triangular,  basal  piece,  running  off 
from  which  are  two  small,  rodlike  pieces  known  as  the  lora. 

b.  The  mentinn.  This  is  a  large,  pear-shaped  piece  attached  to 
the  submentum. 

c.  TJie  labial  palps.  The  labial  palps  are  greatly  modified,  form- 
ing two  long,  four-jointed  structures  grooved  on  the  inner  edge. 
When  these  are  fitted  together,  they  form  a  tube  which  in  turn  is 
inclosed  by  the  laeinia  galea  of  the  maxillae. 

d.  TJie  paraglossa.  This  is  a  sheathlike  arrangement  which 
incloses  the  base  of  the  tongue,  lies  median  to  the  palps,  and  is 
attached  to  the  mentum. 

5.  Tongue.  The  tongue  is  a  long,  flexible  rod,  densely  covered 
with  hairs.  Along  the  ventral  side  there  is  a  deep  groove,  forming 
almost  a  complete  tube,  and  at  the  end  is  a  flaplike  structure  known 
as  the  flabellum. 

Exercise  43.  Make  a  careful  drawing  of  the  mouth-parts  of  the  honey-bee, 
showing  the  above  structures  in  detail. 


CHAPTER  XXI 

THE  LIFE  HISTORY  OF  INSECTS 

Section  XVII.  Life  History  of  a  Plant-Louse 
(Family  Aphididae) 

Material.  The  family  Aphididae  probably  furnishes  some  of  the  best  ex- 
amples for  the  study  of  incomplete  metamorphosis  of  insects.  It  does  not 
matter  much  what  particular  species  is  selected  for  this  work,  as  any  of  the 
ordinary  aphids  attacking  greenhouse  plants  will  be  found  quite  satisfactory. 
Among  the  forms  most  easily  managed  may  be  mentioned  the  lettuce  aphis  and 
the  rose  aphis.  These  may  almost  always  be  secured  at  any  time  of  year.  For 
work  on  the  lettuce  aphis  each  student  should  be  provided  with  a  flowerpot 
in  which  is  growing  one  small  lettuce  plant.  The  instructor  should  keep  on 
hand  a  supply  of  aphids.  These  should  be  grown  on  lettuce  under  a  large  bell 
jar,  to  prevent  the  escape  of  the  winged  forms.  Each  student  should  be  given 
one  wingless,  viviparous  female  just  before  the  insect  reaches  maturity. 

It  will  be  recalled  that  the  life  history  of  the  Aphididae  may  vary 
considerably  with  the  different  species.  Nearly  all  of  them,  how- 
ever, have  two  forms  of  reproduction,  known  as  viviparous  repro- 
duction (in  which  the  living  young  are  brought  forth  without  the 
fertilization  of  the  female  by  the  male)  and  oviparous  reproduction 
(in  which  eggs  are  deposited  by  fertilized  females).  The  sexual 
forms  are  usually  brought  forth  in  the  fall  by  a  viviparous  female, 
and  after  mating,  the  oviparous  female  deposits  eggs  which  are  not 
hatched  until  the  next  spring.  From  these  eggs  are  hatched  the 
viviparous  females,  this  form  of  reproduction  continuing  throughout 
the  summer.  It  will  also  be  recalled  that  of  the  viviparous  forms 
part  may  be  winged  and  part  wingless. 

Exercise  44.  Watch  the  viviparous  female  carefully  and  write  up  a  detailed 
set  of  notes,  including  the  following  observations  : 

1.  Date  of  birth  of  first  young,  giving  the  hour  when  the  observation  was  made. 

2.  Date  of  birth  of  subsequent  young,  giving  the  number  of  young,  the  day, 
and  the  hour  when  observed.  Be  sure  that  only  one  viviparous  female  is  present 
on  each  culture,  and  keep  careful  track  of  all  the  offspring. 

298 


THE  LIFE  HISTORY  OF  INSECTS  299 

3.  Number  the  offspring  consecutively,  according  to  age,  and  note  which 
developed  into  winged  and  which  into  wingless  forms. 

4.  Note  the  age  at  which  each  of  these  individuals  begins  reproduction.  It 
might  be  suggested  that  when  the  first  of  this  generation  begins  reproducing, 
it  is  best  to  remove  the  young  in  order  to  prevent  confusion  of  the  generations. 

Exercise  45.  Make  a  chart  from  your  above  notes,  giving  the  number  of  the 
individual,  whether  winged  or  wingless,  date  of  birth,  date  of  maturity  (when 
first  young  is  produced). 

Exercise  46.  Notes  on  the  rapidity  of  growth.  Isolate  some  newly  born 
individuals,  noting  the  date  and  hour  of  birth.  Watch  these  carefully,  and  note 
the  date  and  the  hour  that  molting  occurs.  The  cast  skin  will  usually  be  found 
near  the  young  aphids,  which  begin  feeding  soon  after  molting.  Those  indi- 
viduals just  having  molted  will  be  found  to  be  the  lightest  in  color,  but  the  cast 
skin  should  be  taken  as  the  only  proof  that  the  insect  has  molted.  As  soon  as 
these  individuals  begin  to  reproduce,  tabulate  your  above  notes,  giving  the 
number  of  hours  between  each  molt  for  each  individual. 

Exercise  47.  Write  up  a  detailed  set  of  notes  describing  one  wingless  in- 
dividual after  each  molt,  up  to  and  including  the  adult  form,  noting  all  the 
changes  which  may  occur. 

Exercise  48.  Write  up  a  detailed  set  of  notes,  similar  to  the  above,  for  the 
winged  form. 

Exercise  49.  Mount  a  wingless  individual  in  the  alcohol-glycerin  solution 
and  make  a  drawing  of  the  dorsal  view.  (The  aphids  should  first  be  dipped  in  95 
per  cent  alcohol,  and  may  then  be  mounted  directly  in  the  glycerin  solution.) 

Exercise  50.  Mount  a  winged  individual  in  the  alcohol-glycerin  solution 
and  make  a  drawing  of  the  dorsal  view. 


Section  XVIII.    Life  History  of  the  Dragon-Fly 

Material.  It  will  be  quite  impractical  for  a  class  in  elementary  entomology 
to  try  to  trace  the  complete  life  history  of  the  dragon-fly,  but  this  form  will 
give  the  student  a  good  idea  of  the  habits  and  structure  of  aquatic  nymphs. 
The  dragon-flies  deposit  their  eggs  on  water  plants,  and  as  soon  as  these  hatch, 
the  young  nymphs  settle  to  the  bottom  of  the  pond  and  may  be  found,  at  almost 
any  time  of  the  year,  crawling  about  in  decaying  vegetation  or  other  sediment. 
The  easiest  way  to  secure  them  is  to  rake  out  the  sediment  from  the  quiet  pools 
of  a  stream,  or  from  the  edge  of  ponds,  with  an  ordinary  garden  rake.  The 
nymphs,  together  with  a  small  amount  of  sediment,  should  be  placed  in  an 
aquarium  until  ready  for  observation.  This  applies  especially  to  material  collected 
in  the  fall,  as  it  will  be  difhcult  for  each  individual  student  to  provide  food  and 
suitable  conditions  for  the  nymphs  that  he  may  have  under  his  observation. 

When  this  work  is  undertaken  by  a  class,  each  student  should  be  provided 
with  a  glass  dish  containing  three  or  four  of  the  largest-sized  nymphs.  As  it  is 
necessary  to  feed  the  nymphs  on  other  aquatic  insects,  it  might  be  better  not 
to  collect  the  material  until  early  spring. 


300         ELEMENTARY  ENTOMOLOGY 

Exercise  51.  Obseri'a/io/is  on  the  structure  of  i/ie  nymphs.  Write  up  a 
careful  description  of  the  nymphs,  noting  the  details  of  structure.  In  the 
description,  refer  to  and  use  the  terms  with  which  you  have  already  become 
familiar  in  your  description  of  other  forms. 

Exercise  52.  Habits  of  the  nymphs.  Make  as  many  notes  as  possible  on 
the  general  habits  of  the  nymphs,  noting  their  methods  of  feeding,  locomotion, 
secreting  themselves,  etc.  (see  page  98). 

Exercise  53.  Observations  on  the  transfoiinaiion  of  nymphs.  Note  care- 
fully whether  or  not  the  nymph  molts,  or  sheds  its  skin,  and,  if  observed,  how 
the  act  is  performed.  Toward  spring  the  nymphs  should  be  placed  in  the  sun- 
light as  much  as  possible.  Each  dish  should  also  be  provided  with  a  number 
of  sticks,  up  which  the  nymphs  may  crawl  when  they  are  ready  to  transform  to 
the  adult  stage.  If  possible,  observe  this  transformation  and  write  up  a  com- 
plete set  of  notes  on  the  subject. 


Section  XIX.    Complete  Metamorphosis,    Life  History  of 
THE  Cabbage  Butterfly  {Pontia  rapae) 

Material.  The  following  instructions  have  been  prepared  especially  for  the 
study  of  the  cabbage  butterfly,  though  the  life  history  of  any  of  the  other  Lepi- 
doptera  may  be  studied  in  the  same  manner,  substituting,  of  course, -the  proper 
food  plants.  Each  student  should  be  provided  with  a  flowerpot  in  which  is  grow- 
ing a  young  cabbage  plant.  If  this  work  may  be  begun  by  the  middle  of  Septem- 
ber, cabbage  butterflies  should  be  collected  and  one  pair  placed  in  each  of  a 
number  of  breeding  cages  (see  Chapter  XXIII).  The  pots  containing  the  young 
plants  can  be  placed  in  the  cages,  and  daily  observations  made  for  the  presence 
of  eggs.  After  the  eggs  hatch,  a  large  lantern  globe,  the  top  of  which  has  been 
covered  with  cheesecloth,  should  be  placed  over  each  plant,  to  prevent  the 
escape  of  the  larvae. 

Exercise  54.  Egg  deposition.  The  student  should,  if  possible,  determine 
and  make  notes  of  the  following  points : 

1.  On  what  part  of  the  leaf  are  the  eggs  deposited .-^ 

2.  Are  they  deposited  in  clusters  or  singly.-* 

3.  The  number  of  eggs  deposited  by  one  female. 

4.  The  period  of  incubation. 

5.  Describe  and  make  drawings  of  the  eggs. 

Exercise  55.  Observations  on  the  larva.  Determine  and  make  notes  of  the 
number  of  molts,  describing  each  of  the  larval  stages. 

Exercise  56.  Observations  on  the  pupce.  If  possible,  observe  the  transfor- 
mation of  the  larvae  to  the  pupal  form.  Note  the  locality  selected  for  pupation, 
the  attachment  of  the  pupa,  and  length  of  time  in  the  pupal  stage.  Also  draw 
and  describe.  (After  pupation  the  pupse  should  be  removed  to  a  cool,  dark 
place  and  left  until  spring,  or,  if  wanted  for  more  immediate  use,  they  should 
be  placed  in  a  light,  warm  room,  where  they  will  probably  emerge  in  a  short 


THE  LIFE  HISTORY  OF  INSECT'S  30 1 

time.  Low  temperatures  are  not  injurious,  but  too  much  moisture  must  be 
avoided.  The  latter  part  of  March  the  pupae  may  be  brought  out  and  again 
placed  under  observation.) 

Exercise  57.    The  emergence  of  the  adult.    Note  the  date  and  the  method 
of  emergence,  and  write  a  brief  description  of  the  adult. 


Section  XX.    Complete  Metamorphosis.    Life  History  of 
THE  Fruit-Fly  {Drosophila  sp.) 

Material.  Material  for  this  work  may  be  secured  by  placing  decaying 
bananas  in  the  sunlight  for  a  few  days.  The  material  should  then  be  cov- 
ered with  a  bell  jar  and  used  as  a  stock  culture.  Each  student  should  be  pro- 
vided with  a  glass  tumbler  containing  about  one  fourth  of  an  inch  of  decayed 
banana.  Cut  a  piece  of  black  paper  the  size  of  the  tumbler  and  lay  on  top  of 
the  banana,  and  cover  the  tumbler  securely  with  a  glass  plate.  The  student 
should  then  place  three  or  four  adult  fruit-flies  in  the  tumbler. 

Exercise  58.  Write  up  a  careful  set  of  notes  on  the  following  points : 

1.  Describe,  and  make  a  drawing  of  egg,  which  will  be  deposited  on  the 
black  paper. 

2.  Note  the  length  of  time  of  incubation. 

3.  Describe,  and  make  a  drawing  of  a  larva. 

4.  If  possible,  determine  the  length  of  the  larval  stage. 

5.  Describe,  and  make  a  drawing  of  a  pupa. 

6.  Determine  the  length  of  the  pupal  stage. 

7.  Describe  the  adult,  and  determine  the  distinguishing  characters  of  the 
sexes. 


CHAPTER   XXII 
CLASSIFICATION  OF  INSECTS 

Section  XXI.    Classification  of  the  Orders  of  Insects 

Material.  One  of  two  methods  may  be  employed  for  this  work :  (a)  Each 
student  should  be  required  to  make  a  collection  of  insects  containing  repre- 
sentatives of  at  least  eight  of  the  principal  orders.  (/>)  Provide  each  student 
with  a  representative  collection  of  twenty-five  insects.  These  should  be  num- 
bered from  one  to  twenty-five,  and  should  contain  as  nearly  representative 
forms  as  possible. 

Exercise  59.  On  a  sheet  of  paper  place  the  numbers  one  to  twenty-five. 
After  each  number  write  the  order  (to  be  determined  by  the  key)  to  which  the 
corresponding  insect  belongs. 

Section  XXII.    Classification  of  Families 

Material.  Give  each  student  a  collection  representing  as  nearly  as  possible 
the  different  families  of  insects  treated  in  the  key.  It  will  be  found  convenient 
to  place  twenty-five  insects  on  a  block,  each  block  containing  only  the  insects 
of  one  order,  thus  obviating  the  necessity  of  classifying  every  insect  to  its 
order  before  placing  it  in  the  family.  The  insects  should  be  distributed  as 
follows  :  One  block  containing  representatives  of  the  lower  orders  (Neuroptera 
and  Neuropteroid  insects) ;  one  block  of  Hemiptera ;  two  of  Coleoptera ;  two 
of  Lepidoptera ;  one  of  Hymenoptera ;  and  one  of  Diptera. 

Exercise  60.    Classification  of  the  families  of  the  lower  orders. 

On  a  sheet  of  paper  place  the  numbers  one  to  twenty-five.  After  each 
number  write  the  family  (to  be  determined  by  the  key)  to  which  the  corre- 
sponding insect  belongs.  If  possible,  by  referring  to  the  text  or  by  compari- 
son with  a  named  collection,  identify  common  forms  to  genus  and  species. 

Exercise  61.    Classification  of  the  families  of  Hemiptera. 

Exercise  62.    Classification  of  the  families  of  Coleoptera. 

Exercise  63.    Classification  of  the  families  of  Coleoptera. 

Exercise  64.    Classification  of  the  families  of  Lepidoptera. 

Exercise  65.    Classification  of  the  families  of  Lepidoptera. 

Exercise  66.    Classification  of  the  families  of  Hymenoptera. 

Exercise  67.    Classification  of  the  families  of  Diptera. 


302 


CLASSIFICATION  OF  INSECTS  303 

KEY  TO   THE   ORDERS   OF   INSECTS 

The  principles  underlying  the  classification  of  insects  have  already- 
been  discussed  in  the  text.  In  arranging  this  key  an  attempt  has 
been  made  to  eliminate  all  useless  characters  and  to  include  only 
those  families  commonly  encountered.  Possibly  this  elimination  has 
been  carried  too  far  for  some  of  the  extreme  forms  of  the  different 
orders  ;  however,  in  an  elementary  textbook  it  is  not  deemed  prac- 
tical to  include  material  that  would  be  of  use  only  to  the  specialist. 

Several  families  are  included  in  the  key  which  are  not  mentioned 
in  the  text.  This  becomes  necessary  for  the  complete  arrangement 
of  the  key,  and  may  be  of  use  in  aiding  students  to  determine  the 
more  uncommon  families  which  they  may  collect.  In  giving  out 
specimens  for  determination  the  teacher  should,  if  possible,  use 
only  those  families  described  in  the  text. 

The  following  key  is  intended  only  for  the  identification  of  typical 
adult  forms.  An  attempt  has  been  made  to  produce  a  usable  key  in 
preference  to  a  strictly  natural  one.  An  ideal  key  should,  of  course, 
combine  these  two  characteristics,  but  it  has  been  found  necessary 
many  times  to  sacrifice  the  natural  arrangement  for  clearness. 

In  the  production  of  these  keys  the  authors  are  indebted  to  all 
previous  workers  in  entomology.  Due  credit  is  given  in  every  case 
where  a  key  has  been  adapted  from  another  author's  work. 

KEY  TO  THE  ORDERS 

A.      Mouth-parts  adapted  for  biting. 

B.     Without  wings,  or  rudiments  of  wings. 

C.     Mouth-parts  retracted  within  the  head.    (Page  73)    .     .     Aptera 
CC.  Mouth-parts  not  retracted  within  the  head. 

D.      Abdomen  joined  to  thorax  by  slender  petiole.    Ants.    (Page 

243) Hymenoptera 

DD.  Abdomen  broadly  joined  to  thorax. 

E.      Insects  small,  body  antlike  or  louselike  in  form.    Bird-lice  ; 

book-lice;  white  ants.    (Page  103)     .     .     .    Platyptera 

£E.  Insects   of   medium   or   large   size.     Body   not   antlike   or 

louselike  in  form. 

jF.     Head  prolonged  into  beak,  at  the  end  of  which  are 

the  biting  mouth-parts.    Scorpion-flies.    (Page  93) 

Mecoptera 
E/\  Head  not  prolonged  into  beak. 


304  ELEMENTARY  ENTOMOLOGY 

G.     Antennae     filiform.      Cockroaches ;     grasshoppers ; 
walking  sticks.    (Page  76)     .     .     .     Orthoptera 
GG.  Antennae  serrated,  or  of  various  types,  but  not  fili- 
form.   Fireflies,  etc.   (Page  136)  .     .     Coleoptera 
BB.  Winged  insects. 

C.     First  pair  of  wings  horny,  meeting  in  a  straight  line  down  the  back. 
D.      Abdomen  with  forceplike  appendages.     Earwigs.     (Page  87) 

EUPLE.XOPTERA 

DD.  Abdomen  without  forceplike  appendages.    (Page  136) 

Coleoptera 
CC.  First  pair  of  wings  leathery  or  membranous. 

D.      Wings  membranous  ;  the  second  pair,  if  present,  not  folded  in 
plaits  under  first. 
E.      Head  prolonged  into  beak,  at  the  extremity  of  which  are 
the  biting  mouth-parts.    Scorpion-flies.    (Page  93) 

Mecoptera 
EE.  Head  not  prolonged  into  beak. 

F.     Wings  with  but  few  cross  veins.    (Page  243) 

Hvmexoptera 
FF.  Wings  net-veined ;  abdomen  broadly  joined  to  thorax. 
G.      Abdomen  provided  with  two  or  three  long,  many- 
jointed  filaments.    (Page  95)       .     .     Ephemerida 
GG.  Abdomen  without  jointed  filaments. 

H.  Antennae  short,  awl-shaped,  and  inconspicuous  ; 
wings  of  equal  size,  held  horizontal,  vertical,  or 
parallel  to  the  body;  not  rooflike.    Dragon-flies. 

(Page  98) Odonata 

HH.  AntennEE  not  awl-shaped,  more  or  less  prom- 
inent. 
/.    Wings  folded  flat  on  body.    Body  compact, 
antlike,  and  flattened  or  louselike  in  form. 

Platvptera 
//.  Wings  rooflike  over  body;  body  linear.  (Page 

90) Neuroptera 

DD.  First  pair  of  wings  more  or  less  leathery,  with  second  pair 
folded  under  first. 
E.      Wings  clothed  with  hairs.    Caddis-flies.    (Page  93) 

Trichoptera 
EE.  Wings  not  clothed  with  hairs. 

F.      First  pair  of  wings  leathery,  second  membranous.    Not 

alike  in  structure.   (Page  76)       ...     Orthoptera 

FF.  Wings  alike  in  structure,  both  more  or  less  leathery. 

G.     Tarsi  5-jointed.   (Page  90)    .     .     .     Neuroptera 

GG.  Tarsi  less  than  5-jointed.     Stone-flies.    (Page  97) 

Plecoptera 


CLASSIFICATION  OF  INSECTS  305 

AA.  Mouth-parts  adapted  for  sucking. 

B.     Mouth-parts  not  adapted  for  piercing. 

C.     Body  covered  with  scales,  wings  usually  broad.     Butterflies  and 

moths.    (Page  172) Lepidoptera 

CC.  Body  not  covered  with  scales,  wings  comparatively  narrow. 
D.      Mandibles,  if  present,  not  fitted  for  biting. 

E.      Two  pair  of  wings,  fringed  with  hair.   Thrips.    Physopoda 
EE.  One  pair  of  wings  usually  naked,  or  with  microscopic  hairs. 

Flies.   (Page  218) Diptera 

DD.  Mandibles  normally  developed Hymexoptera 

BB.  Mouth-parts  adapted  for  piercing. 

C.     Mouth-parts  consisting  of  a  jointed  tube  containing  the  brisdelike 
mandibles  and  maxillae.    Bugs.    (Page  107)    .     .     .     Hemiptera 
CC.  Mouth-parts  consisting  of  a  fleshy  tube  containing  usually  bristle- 
like mandibles  and  maxillae. 
D.    Wingless  insects  ;   body  laterally  compressed.   Fleas.  (Page  240) 

Siphonaptera 
DD.  Winged  or  wingless  insects,  body  not  laterally  compressed. 
E.     Tarsus  provided  with  single  strong,  hooklike  claw.    Wing- 
less parasitic  lice  of  mammals.    (Page  107).       Hemiptera 
EE.  Tarsus  normal.    Winged  or  wingless  insects.    (Page  218) 

Diptera 

KEY  TO    THE    FAMILIES    OF   APTERA 1 

A.  Abdomen  elongate,  composed  of  at  least  ten  segments;  antennae  many- 
jointed  ;  abdomen  usually  provided  with  a  pair  of  two-or-more-jointed,  fila- 
mentous, or  forceplike  appendages.    (Page  74)    Suborder  I,  Thysanura 

B.     Body  covered  with  scales Lepismidae 

BB.  Body  not  covered  with  scales. 

C.     Abdomen  without  caudal  appendages    .     .     .     Anisophaeridae 
CC.  Abdomen  with  caudal  appendages. 

D.      Caudal  appendages  sickle-shaped Japygidae 

DD.  Caudal  appendages  consisting  of  many-jointed  filaments. 

Campodeidae 
A  A.  Abdomen  composed  of  not  more  than  six  segments;  antennae  of  not 
more  than  eight  segments ;   ventral  spring  usually  present,  but  no  ter- 
minal abdominal  appendages.    Springtails.    (Page  74) 

Suborder  II,  Collembola 
B.     Ventral  spring  present. 

C.     Ventral  spring  attached  on  penultimate  abdominal  segment. 
D.      Abdomen  globular,  only  slightly  longer  than  broad. 

Sminthuridae 
DD.  Abdomen  cylindrical,  longer  than  broad.        Entomobryidae 

1  Revised  from   Dr.  K.  W.  v.  Ualla  Tone's  "  Die  Gattungen   und  Arten  der 
Apterygogenea." 


3o6         ELEMENTARY  ENTOMOLOGY 

CC.  Ventral  spring  attached  to  antepenultimate  abdominal  segment. 

PODURIDAE 

BB.  Ventral  spring  absent Aphoruridae 

THE  EPHEMERIDA 

This  order  includes  only  a  single  family,  the  members  of  which  have  deli- 
cate membranous  wings  with  a  fine  network  of  veins.  The  fore-wings  are 
large,  and  the  hind-wings  much  smaller  or  wanting.  Mouth-parts  rudimentary. 
May-flies.   (Page  95) Ephemeridae 

KEY  TO   THE   FAMILIES   OF  ODONATAi 

A.      Front  and  hind  wings  similar  in  outline,  distinctly  narrow  at  base,  held 
vertically  over  the  back  when  at  rest.    Damsel-flies.    (Page  98)       Sub- 
order Zygoptera 
B.     Wings  with  not  less  than  five  antecubital  cross  veins.  Calopterygidae 
BB.  Wings  with  not  more  than  three,  usually  two,  antecubital  cross  veins. 

Agrionidae 

A  A.  Front  and  hind  wings  dissimilar,  the  hind-wings  being  much  wider  at  the 

base ;    wings  held  horizontally  when  at  rest.     Dragon-flies.    (Page  98) 

Suborder  Axisoptera 
B.     Antecubital  cross  veins  of  first  and  second  rows  usually  meeting  each 

other Libelluudae 

BB.  Antecubital  cross  veins  of  first  and  second  rows  not  meeting  each  other. 
C.     Eyes  meeting  above  in  median  line  of  head  ;  abdomen  with  lateral 

ridges  Aeschnidae 

CC.  Eyes  separate,  or  nearly  so ;  abdomen  without  lateral  ridges. 
D.      Eyes  touching  at  a  single  point,  or  barely  apart. 

CORDULEGASTERIDAE 

DD.  Eyes  distinctly  separated Gomphidae 

THE   PLECOPTERA 

This  order  includes  only  a  single  family,  having  four  membranous  wings, 
the  hind-wings  being  folded  plaitlike  under  the  fore-wings.  The  mouth-parts 
are  biting,  but  slightly  developed.    Stone-flies.    (Page  97)      .     .     .  Perlidae 

KEY  TO   THE  FAMILIES   OF  NEUROPTERA 

A.      Hind-wings  broad  at  base,  the  inner  margin  folded  in  plaits.     Dobsons. 
(Page  90) SlALIDAE 

A  A.  Hind-wings  narrow  at  base,  not  folded  in  plaits. 
B.      Prothorax  greatly  prolonged  into  necklike  stalk. 

^  Revised  from  Kellogg's  "American  Insects." 


CLASSIFICATION  OF  INSECTS  307 

C.     Prothoracic  legs  normal        Raphidiidae 

CC.  Prothoracic  legs  fitted  for  grasping Mantispidae 

BB.  Prothorax  normal. 

C.     Wings  clear,  densely  net-veined. 

D.      Antennae    filiform,    without    terminal    knob.      Lace    wings. 

(Page  92) Chrvsopidae 

DD.  Antennas  filiform,  with  terminal  knob.    Ant-lions.    (Page  93  ) 

Mvrmeleoxidae 

CC.  Wings  more  or  less  opaque,  with  many  longitudinal  but  few  cross 

veins Hemerobiidae 


THE   MECOPTERA 

This  order  includes  only  one  family,  having  four  membranous  wings,  fur- 
nished with  numerous  veins.  The  head  is  prolonged  into  a  beak,  at  the  end 
of  which  are  the  biting  mouth-parts.    Scorpion-flies.    (Page  93)    Panorpidae 

THE  TRICHOPTERA 

This  order  includes  but  one  family,  having  four  membranous  wings,  fur- 
nished with  numerous  longitudinal  but  few  cross  veins ;  wings  more  or  less 
densely  covered  with  hair ;  rudimentary  biting  mouth-parts.  Caddis-flies. 
(Page  93) Phryganeidae 

KEY  TO   THE    PLATYPTERA 

A.      Body  cylindrical,  social  insects  with  white,  antlike  bodies.    White  ants. 

(Page  103) Termitidae 

A  A.  Body  depressed,  if  cylindrical,  not  antlike.    Nonsocial,  louselike  insects. 
B.     Antennae  of  not  more  than  five  segments.    Bird-lice.    (Page  106) 

Suborder  Mallophaga 
C.     Antennas  exposed,  consisting  of  three  or  five  segments. 

D.      With  three-segmented  antennae  ;  tarsi  with  one  claw  ;  infesting 

mammals  only Trichodectidae 

DD.  With  five-segmented  antennas  ;  tarsi  with  two  claws  ;  infesting 

birds  only Philopteridae 

CC.  Antennas  concealed  in  shallow  cavities  on  underside  of  head,  con- 
sisting of  four  segments. 
D.      Tarsi  with  one  claw  ;  infesting  mammals  only     .   Gyropidae 
DD.  Tarsi  with  two  claws  ;  infesting  birds  only    ,     .  Liotheidae 
BB.  Filiform  antennae  of  more  than  five  segments. 

Suborder  Corrodentia 
C.     Wings  well  developed ;  ocelli  present  in  addition  to  the  compound 

eyes.    Bark-lice.    (Page  105) Psocidae 

CC.  Wings  and  ocelli  wanting.    Book-lice.    (Page  105)     .  Atropidae 


3o8  ELEMENTARY  ENTOMOLOGY 

THE  EUPLEXOPTERA 

This  order  includes  a  single  family  the  members  of  which  have  four  wings : 
the  first  pair  are  leathery  or  horny,  meeting  in  a  straight  line  down  the  middle 
of  the  back ;  the  second  pair  are  membranous,  with  numerous  radiating  veins 
folded  lengthwise  like  a  fan  and  then  crosswise  under  the  first  pair.    Earwigs. 

(Page  87) FOKFICULIDAE 

KEY  TO   THE   FAMILIES   OF   ORTHOPTERA 

A.      Third  pair  of  legs  not  adapted  for  leaping. 

B.     Body  oval,  dorsoventrally  compressed.    Cockroaches.    (Page  jj) 

Blattidae 
BB.  Body  elongate,  not  dorsoventrally  compressed. 

C.  First  pair  of  legs  fitted  for  grasping  and  holding  their  prey  ;  prono- 
tum  longer  than  any  of  the  other  body  segments.    Praying  mantis. 

(Page  78) Maxtidae 

CC.  First  pair  of  legs  not  fitted  for  grasping  and  holding  prey ;  prono- 

tum  short.   Walking-sticks.    (Page  80) Phasmidae 

A  A.  Third  pair  of  legs  adapted  for  leaping. 

B.     Antennae  shorter  than  body.    Locusts.  (Page  81).     .     .    Acrididae 
BB.  Antennae  longer  than  body. 

C.     Tarsi   consisting   of   four   segments.     Long-horned    grasshoppers. 

(Page  83) LocusTiDAE 

CC.  Tarsi  consisting  of  three  segments.    Crickets.    (Page  85) 

Gryllidae 

THE   THYSANOPTERA 

This  order  includes  but  a  single  family  of  very  small  insects  with  long, 
narrow,  membranous  wings,  having  but  few  or  no  veins  and  bordered  by  a 
fringe  of  long  hair :  the  tarsi  swollen,  bladderlike,  with  or  without  claws. 

Physopodae 

KEY  TO   THE   FAMILIES   OF  HEMIPTERAi 

A.      Wingless  insects  with  fleshy  unjointed  beak;    parasitic  on  mammals. 
(Suborder  Parasitica.)    Suctorial  lice.    (Page  121)  .     .    Pediculidae 
AA.  Winged  or  wingless  insects,  with  a  jointed  beak. 

B.     First  pair  of  wings  leathery  at  the  base,  membranous  at  the  tip,  the 
tips  overlapping  on  the  back ;  beak  arising  from  front  part  of  head. 

Suborder  Heteroptera 
C.     Antennae  shorter  than  head.    Aquatic  or  shore  insects. 

D.      With  two  ocelli.    Toad-bugs Galgulidae 

DD.  Without  ocelli. 

1  Adapted  from  Kellogg's  "American  Insects." 


« 
CLASSIFICATION  OF  INSECTS 


309 


E.     Hind  tarsus  without  claws. 

F.     Pronotum  overlapping   head    above.     Back-swimmers. 

(Page   108) NOTONECTIDAE 

FF.  Head  overlapping  prothorax   above.    Water-boatman. 

(Page  108) CoRisiDAE 

EE.  Hind  tarsus  with  claws. 

F.     Caudal  end  of  abdomen  furnished  with  a  respiratory 
tube.    Water-scorpions.    (Page  109)  .     .     .     Nepidae 
FF.  Caudal  end  of  abdomen  without  respiratory  tube. 

G.      Hind  legs  flattened,  adapted  for  swimming.    Giant 
water-bug.   (Page  109)  .     .     .     Belostomatidae 
GG.  Hind  legs  slender,  not  adapted  for  swimming. 

Naucoridae 
CC.  Antennae  at  least  as  long  as  head. 

D.      Head  as  long  as  entire  thorax Limnobatidae 

DD.  Head  shorter  than  thorax. 

E.      Last  segment   of  tarsus   more   or   less  split,  with  claws 
inserted  before  apex. 
F.     Body   elongated ;     beak    four-jointed.     Water-striders. 

(Page  109) Hydrobatidae 

FF.  Body  usually  stout  and  oval ;   beak  three-jointed. 

Velidae 
EE.  Last  segment  of  tarsus  entire,  and  with  claws  inserted  at 
apex. 
F.     Antennae  of  three  or  four  segments. 
•  G.     Beak  three-jointed. 

H.      Body  very  long  and  slender    .     .     Emesidae 
HH.  Body  not  long  and  slender. 

/.    Front   legs    with   greatly   thickened  femora. 

Ambush-bugs.    (Page  114)    .     Phvmatidae 

//.  Front  legs  with  normal  femora,  or  at  least  not 

unusually  wide. 

J.    Antennasof  three  segments.  Assassin-bugs. 

(Page  112) Reduviidae 

JJ.  Antennas  of  four  segments. 

K.      Tarsus   of   two   segments :    body  very 
flat.    Flat-bugs  ....     Aradidae 
KK.  Tarsus  of  three  segments. 

L.  Dorsal  portion  of  body  more  or  less 
rounded  ;  beak  long,  reaching  to  or 
beyond  second  coxa.  Shore-bugs. 
Saldidae 
LL.  Dorsal  part  of  body  flat ;  beak  not 
reaching  beyond  second  coxa.  Bed- 
bugs.    (Page  I  14)        ACANTHIDAE 


3IO 


ELEMENTARY  ENTOMOLOGY 


GG.  Beak  four-jointed. 
H.      Ocelli  absent. 

/.  Membrane  of  front  wings  with  two  large  cells 
at  the  base,  from  which  arise  about  eight 
branching  veins.  Red-bugs.  Pyrrhocoridae 
//.  Membrane  of  front  wings  with  one  or  two 
closed  cells  at  the  base,  and  with  no  longitudi- 
nal veins.  Leaf-bugs.  (Page  117)  Capsidae 
HH.  Ocelli  present. 

/.     Front  legs  fitted  for  grasping  prey,  the  tibia 
being  armed  with  spines  and  capable  of  being 
closed  tightly  on  the  femora,  which  are  unusu- 
ally stout.    Damsel-bugs    .     .     .     Nabidae 
//.  Front  legs  not  differing  from  the  others. 
J.     Body  and  legs  very  long  and  slender. 

Stilt-bugs Berytidae 

JJ.  Body  not  unusually  slender. 

K.      Tarsus  two-jointed;  wing-covers  resem- 
bling lace  network.    Lace-bugs.    (Page 

117) TiNGITIDAE 

KK.  Tarsus  three-jointed. 

L.  Membrane  with  four  or  five 
simple  veins  arising  from  its  base. 
Chinch-bug  family.    (Page  120) 

Lygaeidae 
LL.  Membrane  with  many  forked  veins 
springing  from  a  transverse  basal 
vein.    Squash-bugs.    (Page  121) 

Coreidae 
FF.  Antennae  of  five  segments. 
G.      Dorsal  portion  of  body  flat. 

H.      Tibia  with  few  or  no  spines.    Stink-bugs.  (Page 

115) Pentatomidae 

HH.  Tibia  armed  with  rows  of  spines    .    Cydnidae 
GG.  Dorsal  portion  of  body  strongly  convex. 

H.  Prothorax  rounded  in  front,  nearly  straight  be- 
hind ;  lateral  margin  of  scutellum  with  a  furrow 
in  which  the  edges  of  the  wing-covers  fit  when 
closed.  Negro-bugs  .  .  .  Thyreocoridae 
HH.  Prothorax  not  as  above ;  lateral  margin  of 
scutellum  without  furrow.    Shield-backed  bugs. 

Scutelleridae 
BB.  Wings  membranous  or  sometimes  leathery  throughout ;  beak  arising 
from  the  hinder  parts  of  the  lower  side  of  the  head. 

Suborder  Homoptera 


CLASSIFICATION  OF  INSECTS  311 

C.     Beak  evidently  arising  from  head ;    tarsi  three-jointed ;   antennae 
minute,  bristlelike. 
D.      With  three  ocelli ;  males  with  musical  organs.    Cicadas.   (Page 

122) CiCADIDAE 

DD.  With  two  ocelli  or  none ;  males  without  musical  organs. 
E.     Antennae  inserted  on  sides  of  cheek  beneath  the  eyes. 

FULGORIDAE  ^ 
EE.  Antennas  inserted  in  front  of  and  between  the  eyes. 

E.  Pronotum  prolonged  posteriorly  over  the  abdomen  or 
at  least  over  the  scutellum.    Tree-hoppers.    (Page  124) 

Membracidae 
FF.  Pronotum  not  prolonged  above  abdomen. 

G.      Hind  tibia  armed  with  one  or  two  stout  teeth  and 
with  short,  stout  spines  at  tip.    Spittle-insects.  (Page 

124) Cercopidae 

GG.  Hind  tibia  with  two  rows  of  spines.    Leaf-hoppers. 

(Page  125) Jassidae 

CC.  Beak  apparently  arising  from  between  the  front  co.\ae,  or  absent ; 
tarsi  one-  or  two-jointed. 
D.      Hind  femora  fitted  for  leaping;  antennas  of  nine  or  ten  seg- 
ments with  two  bristles  on  apex.    Jumping  plant-lice.    (Page 

127)        Psyllidae 

DD.    Hind  femora  normal ;    antennae  usually  with  less  than  ten 
segments. 
E.      Legs    long    and   slender ;    wings    transparent.     Plant-lice. 

(Page  127) Aphididae 

EE,  Legs  short ;  wings  usually  opaque. 

F.  Tarsus  consisting  of  two  joints ;  body  covered  with  a 
whitish  powder,  male  and  female  each  with  four  wings. 

Aleyrodidae 

FF.  Tarsus  consisting  of  one  joint ;   adult  male  with   two 

wings ;    female  wingless,  with  the  body  scale-like  or 

gall-like  in  form.   Scale  insects.   (Page  129)    Coccidae 

KEY  TO  THE  FAMILIES  OF  COLEOPTERA 

Head  not  prolonged  into  beak.    [Coleopfera  geiutiiia.) 
B.      First  and  second  tarsus  consisting  of  five  segments  ;  third  tarsus  con- 
sisting of  four  segments Section  Heteromera 

C.     Head  without  distinct  neck ;  narrower  than  thorax  and  more  or 
less  inserted  in  it;  body  wall  hard.    Darkling-beetles.    (Page  165) 

Texebrionidae 
CC.  Head  with  distinct  neck  and  as  wide  as  prothorax ;  body  soft  and 

elytra  flexible.    Blister-beetles Meloidae 

BB.  First,  second,  and  third  tarsi  of  same  number  of  segments. 


312 


ELEMENTARY  ENTOMOLOGY 

C.     Tarsi  consisting  of  five  segments     .     .     .     Section  Pentamera 
£).      Antennas  filiform,  with  distinct  cylindrical  segments. 

Tribe  Adephaga 
£.      Legs  adapted  for  swimming,  aquatic  in  habits. 

/^.     Eyes  divided  laterally,  making  apparently  four  compound 
eyes.    Whirligig-beetles.    (Page  140)  .     .     Gvrixiuae 
/^f.  Eyes  not  divided.  Predacious  diving-beetles.  Dvtiscidae 
JSE.  Legs  adapted  for  running ;  terrestrial  in  habit. 

/^.     Antennae  inserted  on  front  of  head  above  base  of  man- 
dibles.   Tiger  beetles.    (Page  137)       .     Cicixdelidae 
/7\  Antennae  inserted  on  sides  of  head  between  base  of 
mandibles  and  eyes.    Predacious  ground-beetles.    (Page 

138) Carabidae 

DD.  Antennae  not  filiform. 

£.     Antennas  capitate  or  clavate      .     .     .  Tribe  Clavicornia 
/^.     Aquatic,   legs   fitted   for    swimming.     Water-scavenger 

beetles.    (Page  141) Hydrophilidae 

/-T^.  Terrestrial,  legs  not  fitted  for  swimming. 

G.     Antennas  moniliform,  the  segments  gradually  en- 
larging toward  the  end ;  elytra  covering  only  basal 
half  of  abdomen.    Rove-beetles   .    Staphylinidae 
GG.  Antennae   of   various  forms  (clavate   or  capitate) ; 
elytra  covering  most  of  abdomen. 
H.      Abdomen  with  six  or  more  ventral  segments ;  an- 
terior coxas  conical ;  antennae  gradually  thickened 
or  clavate.    Carrion-beetles.    (Page  142) 

Silphidae 
////.  Abdomen  with  five  ventral  segments ;  anterior 
coxae  conical  and  projecting  from  the  coxal  cavi- 
ties ;  last  three  segments  of  the  antennas  forming 
a  large  club.  Larder-beetles,  etc.  Dermestidae 
EE.  Antennae  serrate  or  lamellate. 

E     Antennas  serrated.    Saw-horned  beetles.    (Page  144) 

Tribe  Serricornia 

G.      Head  inserted  in  thorax,  which  extends  as  far  as 

compound  eyes  ;  body  elongated  or  elliptical. 

//.       First  two  abdominal  segments  fused  together  on 

ventral  side.    Metallic  wood-borers.    (Page  146) 

Buprestidae 
////.  First  two  abdominal  segments  not  fused.    Click- 
beetles.   (Page  144)    ....     Elateridae 
•  GG.  Head  not  inserted  in  thorax  as  far  as  compound  eyes. 
//.      Head  bent  nearly  at  right  angles  to  thorax,  which 
protrudes  over  it.     Size  usually  less  than  one 
fourth  of  an  inch Ptiniuae 


CLASSIFICATIOxN  OF  INSECTS  313 

HH.  Head  normal,  but  partially  or  nearly  covered  by 
thin  anterior  margin  of  thorax. 
/.    Wing-covers    flexible ;    body    elongated    and 
flattened  ;  antennas  not  enlarged  at  tip.    Fire- 
flies.   (Page  147)     ....     Lampyridae 
//.  Wing-covers  firm  ;   body  not  much  flattened  ; 
antennas  often  enlarged  at  tip.     Checkered- 
beetles       Cleridae 

FF.  Antennas  lamellate,  composed  of  a  stemlike  portion 
on  the  end  of  which  are  a  number  of  flat,  bladelike 

segments Tribe  Lamellicornia 

G.     Antennas  elbowed ;    terminal  lamella  consisting  of 
fixed    transverse    plates.     Stag-beetles.    (Page  148) 

LUCANIDAE 

GG.  AntenncE  not  elbowed ;  terminal  lamella  consisting 

of  flat  plates  which  fold  together.    Leaf  chafers  and 

scavenger-beetles.    (Page  149)      .     Scarabaeidae 

CC.  Tarsus  less  than  five  segments. 

D.      Tarsus  consisting  of  four  segments.    (Page  153) 

Section  Tetramera 
E.      Body  short  and  more  or  less  oval ;  antennas  short. 

F.  Front  of  head  not  prolonged  as  a  short,  broad  beak  ; 
elytra  usually  covering  tip  of  abdomen  ;  larvas  and  adults 
leaf  feeders.    Leaf-beetles.    (Page  153) 

Chrvsomelidae 
FF.  Front  of  head  prolonged  as  a  short,  quadrate  beak ; 
elytra  short,  exposing  tip  of  abdomen.    Pea-  and  bean- 
weevils.   (Page  158) Bruchidae 

EE.  Body  long  and  cylindrical;  antennae  long.    (Page  158) 

Cerambvcidae 

DD.  Tarsus    consisting   of   three    segments ;    comparatively  small 

beetles  with  semispherical  bodies.     Ladybird  beetles.    (Page 

161)   (Section  Trimera) Coccixellidae 

A  A.  Head  prolonged  into  a  beaklike  structure  at  the  end  of  which  are  biting 

mouth-parts. 

B.     The  dorsum  of  the  last  segment  of  the  male  divided  transversely  so 

that,  when  viewed  dorsally,  this  sex  appears  to  have  one  more  body 

segment  than  the  female. 

C.     Mandibles  with  a  scar  of  the  anterior  aspect    .    Otiorhynchidae 

CC.  Mandibles  without  scar  on  anterior  aspect.    Curculios.    (Page  167) 

Curculionidae 
BB.  Dorsum  of  last  segment  of  both  sexes  undivided. 

C.     Tibia  not  serrated.    Bill-bugs  and  granary-weevils.    (Page  i6g) 

Calandridae 
CC.  Tibia  serrated.    Bark-beetles.    (Page  1 70)       ...    Scolytidae 


sc   ^^ ^^rrr^ 


Fig.  437.    Diagram  of  wings  of 

Hepialus  gracilis,  showing  jugum 

(/)  and  similarity  of  venation  of 

fore-  and  hind-wings 

(After  Comstock,  from  Kellogg) 


Fig.  438.  Venation  of  a  tortricid 
moth  (Cacoecia  cenisivora>ia) 

(After  Comstock,  from  Kellogg) 


f^rj  r-f 


Fig.  439.   Venation  of  a  pyralid  moth 
(Py  rails  farinalis) 

cs,  costal  vein  ;  sc,  subcostal  vein  ;  r,  radial 
vein ;  m,  medial  vein ;  c,  cubital  vein ;  a, 
anal  vein.  Note  the  hairlike  projection,  the 
fraenulum,  at  the  base  of  the  hind-wing. 
This  fits  into  a  little  pocket  on  the  fore- 
wing.    (After  Comstock,  from  Kellogg) 


Fig.  440.    Venation  of  a  saturniid 

{Bombyx  niori) 

(After  Comstock,  from  Kellogg) 


314 


a    a 

P"iG.  441.   Venation  of  a  cossid 
{Prioiioxysiiis  robinae) 

(After  Comstock,  from  Kellogg) 


Fig.  442.   ^'enation  of  a  hes- 
perid  {Epargyreus  titynis) 

(After  Comstock,  from  Kellogg) 


ri  f^rs 


Fig.  443.    Venation  of  a  notodontid 

{Notodo7Jta  stragtila) 

(.After  Comstock,  from  Kellogg) 


Fig.  444.    Venation  of  a  geome- 
trid  {Dyspepteris  abortivaria) 

(After  Comstock,  from  Kellogg) 


315 


e^r^ 


Fig.  445.    Venation  of  a  noctuid 
(Ag/viis  ypsilon ) 

(After  Comstock,  from  Kellogg) 


a     a 

Fig.  446.    Venation  of  a  lasio- 
campid  {Malacasomaamtricana) 

(After  Comstock,  from  Kellogg) 


Fig.  447.    Venation  of  a  zygaenid 
[Ctenucha  virgin  tea) 

(After  Comstock,  from  Kellogg) 


Fig.  448.   Venation  of  a  lycaenid 

(  Ch r\iso].  haniis  ihoe) 

(After  Comstock,  from  Kellogg) 


316 


'C2 


Fig.  449.   Venation  of  a  papilionid 

(Papilio  folyxenes) 

(After  Comstock,  from  Kellogg) 


Fig.  450.    Venation  of  an  arctiid 

{Halesidota  tessellata) 

(After  Comstock,  from  Kellogg) 


Fig.  451.  Venation  of  a  nymphalid 
[Basila)xhia  astyaiiax) 

(After  Comstock,  from  Kellogg) 


Fig.  452.    Venation  of  a   pierid 
{PoHtia  protodice) .    ( Enlarged) 

(After  Comstock,  from  Kellogg) 


317 


31 8  ELEMENTARY  ENTOMOLOGY 

KEY  TO   THE   FAMILIES   OF   LEPIDOPTERAi 

A.      Lepidoptera  with  slender  antennae,  the  tips  of  which  are  expanded  or 
dilated.    Mostly  diurnal  in  habits.    Butterflies  and  skippers. 
B.      Dilation  of  antennae  terminated  by  recurved  hook.    Wing  venation 

as  in  Fig.  261.    Skippers.    (Page  174) Hesperidae 

BB.  Dilation  of  antennas  not  terminated  by  recurved  hook. 
C     First  pair  of  legs  normal,  or  simply  reduced  in  size. 

D.      First  pair  of  legs  reduced  in  size.  Wing  venation  as  in  Fig.  448. 

(Page  178) Lycaenidae 

DD.  First  pair  of  legs  normally  developed. 

E.    Front  tibia  without  pads ;  claws  toothed ;  cubital  of  fore- 
wing  three-branched.    Fig.  452.    (Page  178)     .    Pieridae 
EE.  Front  tibia  with  pads ;  claws  not  toothed ;  cubital  of  fore- 
wing  four-branched.    Fig.  449.    Swallowtails.     (Page  175) 

Papilionidae 
CC.  First  pair  of  legs  atrophied,  without  claws ;  wing  venation  as  in 

Fig.  451.   (Page  179) Nymphalidae 

A  A.  Lepidoptera  with  antennae  of  various  forms  but  never  enlarged  at  tip. 
Mostly  nocturnal  in  habits.    Moths. 
B.      Hind-wings  with  not  over  two  complete  anal  veins. 

C.     Second  and  third  median  veins  arising  together ;   w"  not  arising 
from  center  of  discal  cell. 
D.      Humeral  vein  present  in  hind-wing,  arising  at  base  of  costal. 
Fraenulum  absent.    Fig.  446.  (Page  216)     .     Lasiocampidae 
DD.  Humeral  vein  absent ;  fraenulum  present. 

E.      Subcosta  and  radius  of  hind-wing  fused  to  near  apex  of 
discal  cell ;  ocelli  present.    Tiger  moths.    Fig.  450.    (Page 

207) Arctiidae 

EE.  Subcosta  and  radius  of  hind-wing  distinct,  or  but  slightly 

fused. 

E.     Diurnal  moths  with  simple   antennae  and  contrasting 

coloration.    Wood  nymphs     ....     Agarlstidae 

EE.  Nocturnal  moths  with  simple  or  pectinate  antennae  and 

without  contrasting  coloration. 

G.      Ocelli  absent ;    antennae  pectinate.     Tussock-moth. 

(Page  203) Liparidae 

GG.  Ocelli    present ;    antennas    usually    simple.     Owlet 
moths.    Fig.  445.    (Page  199)    .     .     .    Noctuidae 
CC.  Second  and  third  median  vein  not  arising  together,  arising  from 
center  of  discal  vein. 
D.      Fraenulum  present. 

E.      Subcosta  and  radius  of  hind-wing  connected  near  base  by 
crossbar.    Hawk  moths.    (Page  208)    .     .     .  Sphingidae 

1  This  key  has  been  adapted  from  keys  of  Holland,  Smith,  Bunter,  and  others. 


CLASSIFICATION  OF  INSECTS  319 

EE.  Subcosta  and  radius  of  hind-wing  not  connected  by  crossbar. 

E.  Moths  with  heavy  abdomens  and  narrow,  strong  fore- 
wings.    Prominents.    Fig.  443.    (Page  193) 

NOTODONTIDAE 

EE.  Moths  with  narrow,  slender  abdomens,  and  broad,  deli- 
cate wings.    Fig.  444.    (Page  195)      .     C}eometridae 
DD.  Fraenulum  absent. 

E.      Tongue  absent ;  tibia  without  spurs.    Fig.  440.   (Page  212) 

Superfamily  Saturxoidea  ^ 
EE.  Tongue  present ;  tibia  with  spurs.    Royal  moths. 

Ceratocampidae 
BB.  Hind-wing  with  three  complete  anal  veins. 

C.     Wings  transparent,  free  from  scales.    Fore-wings  narrow.    Clear- 
winged  moths.    (Page  192) Sesiidae 

CC.  Wings  covered  with  scales. 

D.      Hind-wings  with  subcosta  fused  with  or  approximate  to  radius. 

Fig.  439.   (Page  187)       Pvraudae 

DD.  Hind-wings  with  subcosta  and  radius  far  apart. 

E.      Small    moths   with  fringe    on    inner    angle  of   hind-wing 
unusually  long. 

F.  Second  anal  vein  of  hind-wing  forked  at  base.    Leaf- 
rollers.    Fig.  438.   (Page  186)  .     .     .     Tortricidae^ 

EE.  Second  anal  vein  of  hind-wing  not  forked  at  base.    Leaf- 
miners.    (Page  184) TiNEIDAE 

EE.  Large  or  medium-sized  moths,  without  unusual  fringe  on 
hind-wing. 
E.     Anal    veins    of    fore-wing    partially   fused.     Bag-worm 

moths  PSYCHIDAE 

EE.  Anal  veins  of  fore-wing  not  fused.    Carpenter  moths. 
(Page  191) CossiDAE 


KEY  TO   THE  FAMILIES  OF  HYMENOPTERA3 

Posterior  trochanter  consisting  of  two  segments  ;  ovipositor  modified  into 
a  saw,  or  borer. 
B.      Abdomen  broadly  joined  to  thorax. 

C.     Tibia  of  forelegs  with  two  terminal  spurs ;   female  with  sawlike 

ovipositor.    Saw-flies.    (Page  244)    ....     Tenthredinidae 

CC.  Tibia  of  foreleg  with  one  terminal  spur ;  female  with  ovipositor 

fitted  for  boring.    Horn-tails.    (Page  246)      ....  Siricidae 

BB.  Abdomen  joined  to  thorax  by  slender  petiole. 

1  Includes  families  Bombycidae,  Saturniidae. 

2  Includes  families  Grapholithidae,  Conchylidae,  and  Tortricidae. 
^  Modified  from  Cresson. 


320 


ELEMENTARY  ENTOMOLOGY 


C.     Fore-wings  with  few  or  no  cross  veins ;  if  a  few  cross  veins  are 
present,  the  abdomen   is    not  compressed.    \'ery  small   parasitic 
Hymenoptera. 
D.      Ovipositor  issuing  before  apex  of  abdomen    .     Chalcididae 
I?D.  Ovipositor  issuing  from  apex  of  abdomen.    (Page  253) 

PROCTOTRYPID.A.E 
CC.  Fore-wings  with  one  or  more  closed  cells. 

D.      Fore-wings  without  a  stigma,  or  costal  vein.    Gall-flies.   (Page 

246)  CVXIPIDAE 

D£>.  Fore-wings  with  a  stigma. 

E.      Fore-wing  with  two  recurvent  veins     .     Ichxeu.monidae 
EE.  Fore-wing  with  one  recurvent  vein       .     .       Bracoxidae 
A  A.  Posterior  trochanter  consisting  of  a  single  segment. 
B.      Fore-wings  with  no  closed  submarginal  cells. 

C.     Abdomen  long  and  slender  ;  antennas  long  and  filiform. 

Pelecixidae 
CC.  Abdomen  short,  but  little  longer  than  the  head  and  thorax  together ; 
antennae  short  and  elbowed.    Cuckoo-fiies  .     .     .     Chrysididae 
BB.  Fore-wings  with  at  least  one  closed  submarginal  cell. 

C.     First  abdominal  segment,  and  sometimes  the  second,  forming  a 
knot,  or  node,  on  the  upper  side  of  the  petiole.    Ants.    (Page  254) 

Superfamily  FOR.MICIXA 
D.      First  segment  of  the  abdomen  forming  the  petiole. 

E.     Abdomen  somewhat  constricted  between  the  second  and 

third  segments ;  sting  present Poxeridae 

EE.  Abdomen  not  constricted  between  the  second  and  third 

segments :  sting  absent Campoxotidae 

W.  Petiole  consisting  of  the  first  and  second  segments  of  abdomen  ; 

sting  present IMvrmicidae 

CC.  Petiole  normal,  without  scales  or  nodes. 

£>.      First  segment  of  tarsus  of  hind-leg  cylindrical,  and  naked,  or 
wdth  little  hair. 
E.     Wings  folded  longitudinally  when  at  rest.    True  wasps. 

(Page  263) Superfamily  Vespixa 

E.     Antennae  clavate  or  knobbed  at  tip    .     .     Masaridae 
EE.  Antennas  filiform  or  nearly  so. 

G.      Tibia  of  second  pair  of  legs  with  a  single  terminal 

spur Eumexidae 

GG.    Tibia  of  second  pair  of  legs  with  two  terminal 
spurs.     Tarsal  claws  simple.     (Page   264) 

Vespidae 
EE.  Wings  not  folded   longitudinally  when   at  rest.    Digger- 
wasps.    (Page  260) Superfamily  Sphecixa 

E.     Sides  of  the  pronotum  extending  back  to  the  base  of 
the  wings. 


CLASSIFICATION  OF  INSECTS  32 1 

G.      First  abdominal  segment  distinctly  separated  from 
the  second  on  the  ventral  side  by  a  constriction. 
H.      Tibia  of  second  pair  of  legs  with  two  terminal 
spurs;    females  wingless.    Velvet  ants.    (Page 

261) MUTILLIDAE 

HH.  Tibia  of  second  pair  of  legs  with  single  terminal 

spur SCOLIIDAE 

GG.  First  and  second  segment  of  abdomen  not  separated 
on  ventral  side  by  constriction.    (Page  261) 

PSAMMOCHARIDAE 

FF.  Prothorax  forming  a  narrow  collar,  not  reaching  to  base 
of  wing. 
G.     Base  of  abdomen  with  a  long,  slender  petiole.  (Page 

262) Sphecidae 

GG.  Base  of  abdomen  without  long,  slender  petiole. 

Bembecidae 
DD.  First  segment  of  tarsus  of  hind-leg  expanded  and  flattened, 
furnished  with  numerous  hairs,  often  poorly  developed  in  para- 
sitic bees.    Bees.    (Page  266)  ....      Superfamily  Apina 
E.      Glossa  short  and  flat,  no  longer  than  the  mentum.    Short- 

tongued  bees.    (Page  267) Axdrenidae 

EE.  Glossa  long  and  slender,  not  flattened.    Long-tongued  bees. 
(Page  267) Apidae 

KEY  TO   THE   MORE   IMPORTANT   FAMILIES   OF   DIPTERAi 

A.      Adults  nonparasitic  upon  the  warm-blooded  vertebrates;  habits  variable. 
Abdomen  distinctly  segmented.    Rarely  viviparous. 
B.     Anal  cell  rarely  narrowed  at  the  margin  ;  antennas  consisting  of  more 
than  5  joints,  usually  elongate,  filiform,  and  verticellate,  rarely  pecti- 
nate or  with  a  differentiated  style  or  arista      .     .     .     Nematocera 
C.     Veins  of  the  wings  covered  with  hairs,  the  usual  cross  veins  want- 
ing.   Small  mothlike  flies Psvchodidae 

CC.  Veins  and  margin  of  the  wings  fringed  with  scales.    Mosquitoes. 

(Fig.  455) Culicidae 

D.      Thorax  with  a  distinct  V-shaped  suture ;  wings  variable.   Crane- 
flies.   (Fig.  453) Tipulidae 

DD.  Thorax  without  the  distinct  V-shaped  suture. 

E.      Discal  cell  present.    False  crane-flies    .     .     .   Rhyphidae 
EE.  Discal  cell  wanting. 

F.     Wings  with  few  longitudinal  veins  ;  tibiae  without  spurs. 

Gall-gnats.    (Fig.  458) Cecidomyiidae 

FF.    Tibiae    with    spurs ;     coxae    elongate.      Fungus-gnats. 
(Fig.  459) Mycetophilidae 

^  By  C.  W.  Johnson,  Curator  Boston  Society  of  Natural  History. 


Fig.  453.    Venation  of  a  tipulid  {Protoplasa  fitchii) 
(After  Comstock) 


)-4»S 


Fig.  454.   Venation  of  Blepkarocera  sp. 
(After  Comstock) 


Fig.  455.    Venation  of  a  mosquito  {Cii/ex  sp.) 
(After  Comstock) 


r'       7-2*3 


Fig.  456.    Venation  of  a  Chironomiis  sp. 
(After  Comstock) 


Fig.  457.   Venation  of  a  soldier-fly  (Stratiofnyia  sp.) 

(After  Comstock) 

322 


CLASSIFICATION  OF  INSECTS 


323 


G.     Abdomen  slender ;  wings  narrow  ;  antennae  plumose 

in  the  males.    Midges.   (Fig.  456)    Chironomidae 

GG.  Abdomen  short  and  thick  ;  antennae  shorter  than  the 

thorax,  nonplumose. 

H.      Wings  very  broad,  anterior  veins  stout,  the  other 

weak.    The  black-flics .     .     .     .      Slmuliidae 

HH.  Wings  large  but  more  normal  in  character  ;  legs 

strong,  front  femora  often  thickened. 

BiBlONIDAE 

BB.  Anal  closed  or  distinctly  narrowed,  second  vein  never  fucate  ;  antennae 
usually  with  three  joints,  the  third  joint  sometimes  complex  and  com- 
posed of  numerous  annuli Brachvcera 

C.     Third  joint  of  the  antennas  with  from  4-  to  8-segmented  annuli. 
D.      Squamae  rather  large :   third  joint  of  the  antennas  without  a 

style  or  arista.    Horse-flies Tabaxidae 

DD.  Squamae  small  or  vestigial. 

E.  Costal  vein  does  not  extend  beyond  the  tip  of  the  wing, 
longitudinal  veins  covered  anteriorly  ;  posterior  veins  often 
weak;  tibiae  without  spurs.    Soldier-flies.    (Fig.  457) 

Stratiomyidae 

EE.  Costal  vein  encompasses  the  wing  ;  posterior  veins  strong ; 

middle  tibiae  at  least  with  distinct  spurs  ;  antennae  extremely 

variable Leptidae 

CC.  Third  joint  of  antennae  simple,  not  composed  of  numerous  annuli. 
D.      Antennae  long,  clavate,  apparently  4-jointed ;    palpi  small  or 

wanting.    Mydas-flies Mydaidae 

DD.  Antennae  3-jointed,  often  with  a  variable  style  or  arista ;  palpi 

always  present,  usually  prominent.    Robber-flies    .     Asilidae 

E.      Antennae  apparently   2-jointed ;    anterior  veins   stout,  the 

others  weak   and    extending   obliquely  across    the  wing. 

Small  hunch-backed  flies Phoridae 

EE.  Antennae  2-  or  3-jointed ;  head  small ;  squamae  very  large  ; 
abdomen  inflated.    Parasitic  on  spiders      .     .     Cyrtidae 
E.     Third  antennal  joint  usually  with  a  terminal  style,  pro- 
boscis often  prominent ;  body  frequently  covered  with 
long,  delicate  hairs.    Bee-flies.  (Fig.  460)  Bombyliidae 
EF.  Third  antennal  joint  without  terminal  style  ;  fourth  vein 
terminates  at  or  before  the  tip  of  the  wing.    Window- 
flies   SCENOPINIDAE 

G,     Small,  for  the  most  part  bright-colored  green  or  blue ; 
second  boscal  cell  confluent  with  the  discal  cell ;  arista 
dorsal  or  terminal.    Predacious.    Dolichopodidae 
GG.  Small,  not  brightly  colored ;  head  small,  eyes  some- 
times contiguous ;  proboscis  rigid.    Predacious. 

Empididae 


Fig.  458.    Venation  of  a  cecidomyiid  gall-gnat 
(After  Comstock) 


Fig.  459.   Venation  of  a  fungus-gnat  {I\Iycetophilidae) 
(After  W'innertz,  adapted  from  Comstock) 


yS  13 


la    cu^     m3+cu' 

Fig.  460.   Venation  of  a  bombyliid  {Peniarbes  capita) 

(After  Comstock) 


"cvJyla 

Fig.  461.    Venation  of  a  bot-fly  {Gastrophihis  sp.) 
(After  Comstock) 
324 


CLASSIFICATION  OF  INSECTS 


325 


H.      Third  joint  almost  always  with  a  dorsal  arista  ;  a 

spurious  longitudinal  vein  between  the  third  and 

fourth  longitudinal  veins ;  first  posterior  cell  al- 

waysclosed.  Flower-flies.  (Fig. 463)  Svrphidae 

HH.  No  spurious  longitudinal  veins. 

/.  Small ;  hind  tarsi  enlarged  and  often  orna- 
mented in  the  male  arista  terminal.  Flat- 
footed  flies Platypezidae 

//.  Small ;  head  large,  composed  chiefly  of  eyes ; 
arista  dorsal.    Big-eyed  flies.    Pipuxculidae 
/.    Squamae  small  or  vestigial ;  eyes  never  con- 
tiguous ;  the  front  in  both  sexes  of  equal 
width ;  thorax  vnthout  complete  transverse 

suture Acalvpterae 

K.  Auxiliary  vein  distinct,  the  first  vein 
ends  near  or  beyond  the  middle  of  the 
wings ;  a  distinct  bristle  on  each  side 
of  the  face;  oval  vibrissae  present ;  front 
usually  with  well-developed  bristles  and 

hairs Cordvluridae 

KK.  Front  never  brisdy  near  the  antennas ; 
abdomen    cylindrical,   contracted    near 
the   base.     Small  shining    black  flies. 
Cheese-maggot,  etc.     .     .     Sepsidae 
L.     No   oral  vibrissae ;    abdomen  elon- 
gate,   often    narrowly    constricted, 
proboscis  long  and  folded  near  the 
middle.    (Fig.  462)     .     Conopidae 
LL.  Upper    fronto-orbital    bristles    only 
present;  preapical  tibial  bristle  rarely 
present ;  arista  rarely  plumose  ;  ovi- 
positor horny ;    wings  usually  pic- 
tured       Ortalidae 

M.  Fronto-orbital  bristles  present 
or  absent ;  second  joint  of  the 
antennas  often  elongate  ;  arista 
plumose ;  preapical  tibial  bristle 
present;  ovipositor  not  horny; 
wings  often  pictured.  Meadow- 
flies  .  .  .  SCIOMYZIDAE 
MM.  One  or  two  fronto-orbital  bris- 
tles ;  third  joint  of  the  antennae 
more  or  less  elongate ;  preapical 
bristle  absent  or  present.  All 
small  species.   Sapromyzidae 


cu*ia 

Fig.  462.    Venation  of  a  conopid  {Coiiops  affinis) 
•(After  Comstock) 


sc    r'    r2*3  Y**5 


Fig.  463.    Venation  of  a  syrphid  {Eristalis  sp.) 
(After  Comstock) 


la   ciiz  ^^^ 

Fig.  464.    Venation  of  a  dixa  midge  {Dixa  sp.) 
(After  Comstock) 


Y4*S 


Fig.  465.  Venation  of  an  empidid  {^Rhamphomyia  sp.) 

(After  Comstock) 
326 


CLASSIFICATION  OF  INSECTS  327 

N.  Auxiliary  vein  absent  or  in- 
complete; first  vein  usually 
ends  in  the  costa  before  the 
middle  of  the  wing;  head 
produced  on  each  side  into 
a  lateral  process  for  the 
eyes    .     .     .     Diopsidae 

NN.  Hind  metatarsi  incrassated 
and  usually  shorter  than  the 
second  joint ;  oval  vibrissae 
present.  Small  fiies  about 
excrement  near  water. 

BORBORIDAE 

O.  Discal  and  basal  cells 
united,  anal  cell  absent; 
front  bare  or  at  most 
bristly  above.  Small, 
usually       light-colored 

flies     .       .       OSCINIDAE 

00.  Front  often  brisdy, 
face  often  very  convex, 
mouth  cavity  usually 
large ;  no  oval  vibrissas. 
Small  dark-colored  flies 
about  water. 

Ephvdridae 
P.  Anal  cell  complete ; 
oral  vibrissas  pres- 
ent ;  aristae  long,  plu- 
mose, or  pectinate 
above.  Vinegar  or 
pomace  flies. 

Drosphilidae 
PP.  Aristabare  or  pubes- 
cent ;  front  bristly 
at  least  as  far  as 
the  middle.  Very 
small  flies,  compris- 
ing most  of  the  leaf- 
miners. 

Agromyzidae 
Q.     Oval  vibrissae  ab- 
sent ;  anal  cell  an- 
gular ;  no  preapi- 
cal  tibial  bristle; 


328         ELEMENTARY  ENTOMOLOGY 

ovipositor  long 
and  jointed ; 
wings  usually 
pictured.  Fruit- 
flies. 

Trypetidae 
QQ.  Anal  cell  not  pro- 
duced ;  antennae 
usually  elongated 
and  decumbent. 
Rather  small 
elongate  flies. 

PSILIDAE 

JJ.  Squamae  large ;  front  of  male  narrowed  or 

eyes    contiguous ;    thorax    with    complete 

transverse  suture      .     .     .     Calvpterae 

K.      Oval  opening  small ;   the  mouth-parts 

small  or  vestigial.  Larvae  parasitic  upon 

mammals.    Bot-flies.    (Fig.  461) 

Oestridae 
KK.  Oval  opening  of  usual  size,  not  vestigial ; 
hypopleurae  with  a  tuft  of  bristles  ;  first 
posterior  cell  narrowed  or  closed ;  arista 
bare  or  somewhat  pubescent.  Larva 
parasitic  upon  the  early  stages  of  other 

insects Tachixidae 

L.     Arista  bare  on  the  outer  half ;  dor- 
sum of  the  abdomen  rarely  bristly 
on  the  anterior  part.    Larva  usually 
feeds  on  decaying  animal  matter. 
Flesh-flies    .     .     Sarcophagidae 
LL.  Arista  entirely  plumose  ;  dorsum  of 
the  abdomen  usually  bristly  on  the 
anterior  part ;  legs  long.  Larva  para- 
sitic on  other  insects    .    Dexiidae 
M.       Arista  plumose;  abdominal  seg- 
ments without   bristles  except 
near  the  tip  ;  first  posterior  cell 
narrowed  or  closed.    House-fly, 

etc MUSCIDAE 

MM.  Arista  plumose,  pubescent,  or 
bare ;  first  posterior  cell  very 
slightly  or  not  at  all  narrowed 
at  the  margin.  Larva  are  vege- 
table feeders.   Axthomvudae 


CLASSIFICATION  OF  INSECTS 


329 


A  A.  Adults  usually  cctoparasitic  upon  warm-blooded  vertebrates;    abdomen 

indistinctly  segmented.    Larva;  born  when  about  to  pupate.       I'upipaka 

/>.      Winged  or  wingless  flies ;  eyes  faceted ;  palpi  forming  a  sheath  for 

the  proboscis  ;  veins  of  the  wing,  when  present,  crowded  anteriorly,  the 

weaker  veins  running  obliquely  across  the  wing.    Parasitic  upon  birds 

and  mammals.    House-flies Mippoboscidae 

BB.  Winged  or  wingless:   when  present  the  wings  are  pubescent,  with 

parallel  veins  and  outer  cross-veins  ;   eyes  usually  unfacetcd ;   ocelli 

wanting ;   antennae  2-jointed ;  palpi  broad,  not  forming  a  sheath  for 

the  proboscis.    Usually  parasitic  upon  bats    ....     Stkeblidae 

C.     Wingless;   halteres  present ;  eyes  vestigial ;  head  folding  back  on 

the  dorsum  of  the  thorax.    Small,  spiderlike  flies ;  parasitic  upon 

bats.    Bat-ticks Nycteribiidak 

CC.  Wingless;  halteres  absent;  eyes  vestigial;  last  joint  of  the  tarsi 
with  a  pair  of  comblike  appendages.  Parasitic  upon  the  honey- 
bee.   Bee-louse Bkaulidae 


CHAPTER    XXIII 

METHODS  OF  COLLECTING  INSECTS 

The  following  instructions  on  the  methods  and  equipment  for 
collecting  and  preserving  insects  have  been  compiled  to  give  as 
concise  information  on  the  subject  as  possible.  Most  of  the  methods 
and  equipment  have  been  tried  and  tested  out  either  by  the  author 
or  under  his  observation.  There  are  a  number  of  accessible  bulletins 
and  papers  on  this  subject,  one  of  the  best  of  which  is  United  States 
National  Museum  Bulletin  No.  6j,  "  Directions  for  Collecting  and 
Preserving  Insects,"  by  Nathan  Banks.^ 

Field  kit.  In  order  to  secure  a  collection  that  is  at  all  valuable, 
it  is  necessary  to  make  special  trips  after  insects,  and  to  be  provided 
with  special  equipment.  Therefore,  among  the  first  requirements 
is  a  means  of  carrying  the  outfit  so  that  every  article  will  be 
accessible. 

TJic  haversack.  This  is  one  of  the  most  common  means  of 
carrying  collecting  outfits,  and  if  constructed  of  the  proper  material, 
will  be  found  very  handy.  The  size  will  depend  somewhat  on  the 
length  of  the  trip  taken,  but  for  ordinary  purposes  a  sack  twelve 
by  fourteen  by  four  inches  will  be  found  most  convenient.  It  should 
be  provided  with  a  good  flap,  to  fasten  by  means  of  a  buckle  or  snap, 
as  well  as  with  shoulder  straps  and  loops  for  the  belt.  These  latter 
are  very  important,  as  they  prevent  the  sack  from  flopping  about 
while  collecting.  Canvas  or  khaki  makes  very  serviceable  sacks,  but 
they  are  not  waterproof.  Some  of  the  numerous  imitation  leathers 
or  heavy  oilcloth  will  wear  nearly  as  long  and  be  much  more 
serviceable.  The  haversack  should  have  at  least  three  separate 
compartments,  and  if  manufactured  at  home,  with  a  little  ingenuity 
one  can  provide  a  place  for  each  article  of  the  outfit. 

Collecting  coat.  Any  comfortable,  loose-fitting  coat  may,  with  a 
little  alteration,  be  converted  into  an  entomologist's  collecting  coat. 
The  requirements  are  a  sufficient  number  of  pockets  to  hold  the 

^  See  also  the  bottom  of  page  359. 
330 


METHODS  OF  COLLECTING  INSECTS 


field  outfit.  The  ordinary  khaki  or  duck's-back  hunting  coat  will 
be  found  very  convenient,  having,  as  it  does,  an  abundance  of 
room  for  accommodating  cyanide  bottles,  folding  nets,  and  other 
necessar}'  articles. 

Collecting  belt  (Fig.  466).  For  short,  half-day  excursions  a  loose- 
fitted,  woven  belt,  about  three  or  four  inches  wide,  provided  with 
pockets  to  hold  cyanide  bottles,  forceps,  storage  boxes,  etc.,  is  veiy 


5^ 

W  *^ 

9 

Qj**-^ 

i^^-'-^i^^.^-'-:;;: 

m 

» 

Fig.  466.    A  collecting  belt 
(.A.fter  Banks) 

serviceable.  The  objection  to  this  affair,  however,  is  the  unavoid- 
able width  of  the  belt.  These  belts  may  be  obtained,  with  a  complete 
collecting  outfit,  from  any  of  the  entomological  supply  companies. 
Insect  nets.  Of  first  importance  to  the  entomologist  is  the  insect 
net.  In  its  simplest  form  the  net  consists  of  a  ring,  or  hoop,  firmly 
attached  to  a  handle  two  or  three  feet  in  length.  Attached  to  the 
hoop  is  a  net  about  eighteen  inches  in  depth.  A  very  serviceable  net 
may  be  constructed  by  bending  a  stout  wire  into  a  circle  (Fig.  467), 
then  bending  the  ends  back  at  right  angles  and  lashing  them 


332 


ELEMENTARY   ENTOMOLOGY 


firmly  to  the  stick  with  stout  binding  wire.  The  ring  will  be  held 
much  more  firmly  if  the  ends  of  the  wire  are  sharpened  and  again 
bent  at  right  angles  and  driven  into  the  stick.  Also,  a  groove  cut  in 
either  side  of  the  stick  for  the  reception  of  the  wire  will  make  it 
much  stouter.  There  are  numerous  other  ways  of  constructing  net 
frames,  but  most  of  them  are  too  complicated  for  practical  use. 
Many  folding  frames  of  various  types  may  be  obtained  of  entomo- 
logical supply  companies,  but  none  of  these  are  equal  to  the  spring- 
steel,  folding  landing  nets  sold  by  dealers  in  fish  tackle.    These 

may  be  obtained  with  a  three-foot,  jointed 
handle,  are  nearly  as  light,  and  will 
stand  much  more  wear  than  any  of  the 
regular  insect-net  frames  on  the  market. 
The  simplest  and  lightest  net  ring  is  that 
of  the  simplex  net  (see  Appendix) ;  this 
consists  of  a  thin  steel  band  which  is 
easily  coiled  up  and  carried  in  the  pocket, 
and  readily  attached  to  the  handle. 
Numerous  materials  are  used  in  the 
construction  of  the  net  itself.  Mosquito 
bar  is  sometimes  used,  but  this  lasts  but 
a  short  time  and  is  too  coarse  to  catch 
small  insects.  A  fine  bobbinet  is  far 
superior  to  the  mosquito  bar,  as  is  also 
cheesecloth.  With  any  of  these  mate- 
rials a  hem  of  stout  cotton  cloth  should 
first  be  sewed  to  the  net,  through  which 
to  run  the  net  frame.  The  net  should  be  about  eighteen  inches  in 
depth,  tapering  nearly  to  a  point. 

The  net  above  described  is  to  be  used  for  all  ordinary  purposes, 
such  as  catching  butterflies,  dragon  flies,  etc.,  but  is  scarcely  suitable 
for  certain  kinds  of  collecting. 

The  sweeping  net.  This  type  of  net  is  very  similar  to  the  one 
just  described,  except  that  the  frame  is  much  heavier  and  the  net 
of  stronger  material,  such  as  denim  or  canvas.  It  is  used  by  sweep- 
ing it  back  and  forth  rapidly  over  the  tops  of  the  bushes,  through 
long  grass,  weed  patches,  etc.  After  sweeping  back  and  forth  a 
number  of  times,  the  net  is  given  a  half  turn,  which  prevents  the 


Fig.  467.    A  wire  net  frame 


METHODS  OF  COLLECTING  INSP:CTS  333 

insects  from  escaping.  An  improved  form  of  this  net  consists  of  an 
outer  sack  with  square  in  place  of  tapering  bottom,  the  sack  to  be 
made  out  of  cheesecloth,  cotton  cloth,  or  some  such  material.  On 
the  inside  of  this  is  fitted  a  short,  funnel-shaped  net  made  out  of 
bobbinet  or  light  cheesecloth.  This  net  has  an  opening  of  about 
two  inches  at  the  bottom.  In  sweeping,  the  insects  pass  down 
through  this  opening  between  the  two  nets  and  are  unable  to  es- 
cape. In  this  way  great  numbers  of  grass  insects  may  be  collected 
without  stopping  to  remove  them  from  the  net.  The  insects  may 
be  stupefied  by  placing  the  entire  net  in  a  pail  together  with  a  piece 
of  cotton  saturated  with  ether. 

For  aquatic  collecting  certain  other  types  of  nets  are  desirable, 
although  the  ordinary  insect  net  may  sometimes  be  used  to 
advantage. 

Water  dip  net  (Fig.  468).  The  frame  of  this  type  of  net  is  usu- 
ally flattened  on  one  side  so  as  to  allow  the  net  to  be  manipulated 


Fig.  46S.    A  water  dip  net  Fig.  469.    A  small  dip  net 

(After  Packard)  (After  Howard) 

closer  to  the  bottom.  The  net  itself  should  be  made  of  fine  brass- 
wire  netting,  about  twelve  inches  in  diameter  and  of  about  the  same 
depth.  Fig.  469  shows  a  dip  net  with  a  flange,  or  lip,  of  tin  or 
sheet  iron,  which  is  useful  in  dislodging  aquatic  larvae  or  insects 
from  around  stones,  thick  weeds,  etc. 

TJic  sag  net  (Fig.  470),  This  form  of  aquatic  net  is  described 
by  Professor  James  G.  Needham,  who  is  probably  our  best  authority 
on  aquatic  insects,  as  follows  : 

It  consists  of  a  ring  of  stout  spring  wire  three  to  four  feet  in  diameter,  to 
which  is  attached  a  very  shallow  bag  of  bobbinet,  and  at  one  side  is  a  handle 
only  long  enough  to  be  held  readily.  It  is  intended  to  catch  insects  adrift  in 
the  stream,  and  is  accompanied  by  an  instrument  for  dislodging  them.  Such 
an  instrument   is  figured   below  the  net.     It  consists   of  a   handle   three  or 


334 


ELEMENTARY  ENTOMOLOGY 


four  feet  long,  with  a  double  hook  at  one  side  and  a  brush  at  the  other  side 
at  its  distal  end.    To  illustrate  the  use  of  this  apparatus,  suppose  we  wish  to 

collect  the  insects  from  the  stones 
obstructing  a  brook.  We  place  the 
net  directly  below  the  obstruction 
and  in  the  current,  and  adjust  it  to 
the  bottom  by  downward  pressure 
on  the  handle  with  one  hand,  while 
with  the  other  we  rapidly  overturn 
the  stone  and  with  a  brush  sweep 
free  the  clinging  insects.  These  are 
driven  by  the  current  into  the  net, 
when  it  is  then  lifted  and  emptied. 


Sag  net,  hook  and  brush  for  col- 
lecting in  rapids 

(After  Needham) 


Fig.  470. 


An  aquatic  sieve  net  (Fig.  471).  This  net  is  intended  to  be  used 
in  stagnant  water  or  on  sandy  bottoms  where  there  is  but  httle 
vegetation.  The  frame  consists  of  a  Hght  steel  rod,  sides  of  heavy 
tin  or  galvanized  iron,  and  a  bottom  of  fine  brass  or  galvanized 


Fig.  471.    An  aquatic  sieve  net 
(After  Needham) 


wire  netting.  When  provided  with  a  long  handle,  this  net  may 
be  used  from  the  shore,  and  is  particularly  recommended  for 
burrowing  nymphs  of  aquatic  insects. 

Rake  net.  The  rake  net  consists  of  an  ordinary  garden  rake, 
with  a  stiff  semicircle  of  wire  fastened  on  the  upper  side  of  the 
rake  above  the  teeth.  This  should  be  braced  to  the  handle  with 
another  piece  of  wire.  A  net  is  then  attached  to  the  upper  part  of 
the  rake  and  around  the  semicircle  of  wire.  This  is  very  useful  in 
slightly  weedy  water,  or  where  there  is  a  large  amount  of  debris 
on  the  bottom.  When  the  bottom  of  a  pond  or  stream  is  raked, 
the  insects,  nymphs,  and  small  crustaceans  are  either  entangled  in 
the  debris  and  brought  to  shore,  or,  in  trying  to  escape  the  rake 
teeth,  swim  back   into  the  net.    The   debris  should  be  carefully 


METHODS  OF  COLLECTING  INSECTS 


t-': 


searched  for  any  nymphs  or  larvae  that  may  be  entangled  in  it. 

This  form  of  net  is  particularly  useful  in  collecting  dragon-fly 
nymphs,  and  is  much  superior  to  the  ordinary 
garden  rake,  which  has  often  been  recommended 
for  this  purpose. 

Cyanide  bottle  (Figs.  472  and  473).  These 
bottles  should  be  provided  in  at  least  three  sizes, 
the  largest  with  a  di- 
ameter of  two  and  one 
half  inches  or  more, 
a  smaller,  straight- 
necked  bottle  with  a 
diameter  of  an  inch 
and  a  half,  and  an- 
other much  smaller 
straight-necked  bot- 
tle with  a  diameter 
of  about  half  an  inch. 
Before  much  collect- 
ing is  done,  the  stu- 
dent will  probably 
find  it  necessary  to 
provide  himself  with 
two  complete  sets  of 
these     bottles,    with 

possibly  one  or  two  extra  of  the  smaller 

sizes.     Cyanide  bottles  are  made  in 

the  following  manner  :    Place  a  few 

good-sized  pieces  of  potassium   cya- 
nide (a  most  deadly  poison)   in  the 

bottom  of  each  bottle,  and  cover  the 

cyanide    with    dry    plaster   of    Paris. 

(As  the  fumes  of  potassium  cyanide 

are    very    poisonous,    it    should    be 

handled  with   extreme  care.)     Then 

mix  up  a  thick  paste  of  plaster  of 

Paris  and  water,  and  pour  over  the  dr}'  plaster  in  the  bottles. 

Leave  standing  open  for  a  few  hours,  until  the  water  has  evaporated 


Fig.  472.    A  cya- 
nide bottle  for  the 
pocket.    (One  half 
actual  size) 


Fig.  473.   A  larger  cyanide  bottle 
with  paper  strips    to    give    sup- 
port to  the  insects 

(After  Banks) 


3J^ 


ELEMENTARY  ENTOMOLOGY 


and  the  plaster  of  Paris  set.  After  this  the  bottle  should  always  be 
kept  corked,  so  as  to  retain  the  strength  of  the  cyanide.  The  ad- 
vantage in  putting  the  dvf  plaster  of  Paris  in  first  is  that  it  absorbs 
the  moisture  and  will  keep  the  bottle  dry  longer  than  if  the  wet 
plaster  is  poured  directly  over  the  cyanide.  It  will  also  be  found 
advantageous  to  place  a  few  strips  of  dry  blotting  paper  in  each 
cyanide  bottle,  as  this  serves  the  double  purpose  of  helping  to 
absorb  the  moisture  and  preventing  the  insects  from  shaking  about. 
After  the  insects  are  caught  in  the  net,  they 
should  be  transferred  to  the  cyanide  bottle, 
which,  if  properly  constructed,  will  stupefy 
them  in  a  few  seconds.  Insects,  especially 
beetles,  should  not  be  removed  from  the 
bottle  for  an  hour,  although  Hymenoptera 
and  Diptera  will  be  killed  within  ten  minutes. 
If  the  cyanide  is  too  dry,  it  does  not  act  so 
rapidly,  and  a  few  drops  of  soda  water  will 
greatly  increase  its  efficiency.  Very  small 
cyanide  bottles  may  be  made  by  placing  a 
piece  of  cyanide  in  the  bottom,  covered  with 
cotton  or  blotting  paper. 

If  possible,  only  insects  of  the  same  size 
should  be  placed  together  in  the  cyanide  bot- 
tles. Fragile  insects,  or  those  with  scaly  wings, 
should  not  be  put  in  with  the  general  collection. 
Chloroform  bottle  (Fig.  474).  While  not  an 
absolute  essential  to  the  collecting  of  insects, 
the  chloroform  bottle  will  be  found  one  of  the 
most  valuable  assets,  especially  to  the  collector  of  Lepidoptera. 
One  of  the  most  convenient  forms  consists  of  a  small-mouthed 
bottle,  into  the  cork  of  which  has  been  inserted  a  camel's-hair 
brush.  These  will  be  found  most  useful  in  collecting  very  small 
insects  or  butterflies.  In  collecting  very  small  insects,  touching  them 
with  a  brush  moistened  in  chloroform  is  sufficient  to  kill  them,  and 
at  the  same  time  the  insects  will  adhere  to  the  brush  and  may 
thus  be  transferred  to  the  storage  bottle  or  box.  In  collecting 
Lepidoptera  the  sides  of  the  thorax  should  be  moistened  with  the 
chloroform  before  placing  them  in  the  c\-anide  bottle. 


Fig.    474.  Chloroform 

bottle    with    a    brush 

stopper 

(After  Banks) 


METHODS  OF  COLLECTING  INSECTS  337 

Another  form  of  chloroform  bottle  suitable  for  stupefying  large 
Lepidoptera  is  made  by  inserting  a  fine-pointed  medicine  dropper 
through  the  cork  of  the  bottle.  A  few  drops  of  chloroform  can  then 
be  applied  directly  to  the  specimens,  through  the  net,  before  they 
are  removed.  This  will  also  be  found  convenient  in  collecting  some 
of  the  larger  Hymenoptera.  Since  the  chloroform  has  a  tendency 
to  harden  the  specimens,  only  a  sufficient  amount  should  be  used 
to  stupefy  the  insects,  which  should  immediately  be  placed  in  the 
cyanide  bottle. 

AlcohoL  This  is  another  accessory  that  should  be  used  in  the 
field  only  in  collecting  very  small  insects,  such  as  Thysanura,  very 
small  larvae,  Aphididae,  etc.  The  alcohol  outfit  should  consist  of 
a  number  of  small,  straight-necked  vials,  fitted  with  cork  stoppers, 
about  half  filled  with  75  per  cent  alcohol.  In  addition  to  these 
vials  the  collector  should  have  a  larger  bottle  and  brush,  similar  to 
the  chloroform  bottle  described  above.  This  bottle  should  contain 
95  per  cent  of  alcohol  and  5  per  cent  of  glycerin.  The  speci- 
mens are  killed  b\'  touching  them  witli  the  brush  moistened  in  the 
95  per  cent  alcohol,  after  which  they  are  washed  off  into  the  bottle 
containing  the  weaker  alcohol.  The  reason  of  this  combination  of 
two  grades  of  alcohol  is  that  many  insects  are  protected  with  a 
waxy  secretion  which  the  weaker  alcohol  will  not  penetrate.  Of 
course,  specimens  should  not  be  collected  in  this  way  unless  they 
are  to  be  preserved  permanently  in  some  liquid  medium.  In  collect- 
ing some  Thysanura  it  may  be  found  necessary  to  dispense  with 
the  glycerin,  although  it  has  a  tendency  to  retain  the  color  better 
than  the  alcohol  alone. 

Collecting  forceps.  While  these  are  not  absolutely  essential  to 
the  field  kit,  it  will  be  found  convenient  to  have  a  pair  of  stout, 
broad-pointed  forceps  for  handling  stinging  Hymenoptera,  some 
beetles,  and  other  insects  that  are  liable  to  injure  the  collector. 
Fine-pointed  forceps  should  also  be  taken  along  to  handle  very 
small  insects,  although  a  moistened  camel's-hair  brush  will  serve 
the  same  purpose. 

Hatchet  and  chisel.  These  tools  will  be  found  very  useful  in 
collecting  wood-boring  insects  and  their  larvae.  The  marble  safety 
ax  stands  in  a  class  by  itself,  being  far  superior  to  anything  else  on 
the  market  for  this  purpose.    Even  in  general  collecting  this  ax  will 


338 


ELEMENTARY  ENTOMOLOGY 


be  found  very  useful  for  numerous  purposes.  In  addition  to  the 
ax,  many  collectors  always  carry  a  chisel,  but  this  will  be  found  of 
but  little  advantage  except  in  collecting  wood-boring  larvae. 

Receptacles  for  carrying  insects.  For  general  collecting,  one 
should  always  carry  a  number  of  receptacles  in  which  to  place  the 
insects  as  soon  as  they  have  been  killed  in  the  cyanide  bottle.    For 


Fig.  475.    The  paper  envelope  for  Lepidoptera,  and  method  of  folding  it 
/,  first  fold  ;  2,  second  fold.    (After  Banks) 


METHODS  OF  COLLECTING  INSECTS  339 

this  purpose  ordinary  pill  boxes  of  various  sizes  are  most  conven- 
ient. Each  box  should  be  partly  filled  with  crushed  tissue  paper, 
to  prevent  the  insects  from  shaking  about.  Care  should  be  taken 
not  to  place  too  many  insects  together.  If  the  insects  cannot  be 
mounted  at  once,  the  date  of  collecting,  the  locality,  and  other 
notes  may  be  written  on  the  outside  of  the  box.  For  very  small 
insects  gelatin  capsules  will  prove  more  useful  than  the  pill 
boxes.  Large-sized  capsules  especially  adapted  to  this  purpose 
may  be  obtained  of  entomological  supply  companies  or  large  drug 
houses.  Glass  bottles  should  never  be  used  for  this  purpose,  as 
the  moisture  from  the  bodies  of  the  insects  soon  causes  them  to 
deteriorate,  or  otherwise  injures  the  more  delicate  specimens. 
Also,  cotton  should  not  be  used  in  the  pill  boxes  or  capsules,  as 
the  claws  and  delicate  hairs  of  the  insects  become  entangled  and 
often  broken  off.  Small  paper  envelopes  will  be  found  very  useful 
in  carrying  Lepidoptera,  but  they  should  be  packed  in  a  tin  or 
wooden  box  to  prevent  crushing. 

Collecting  larvae.  The  method  of  collecting  larvae  depends 
somewhat  upon  the  manner  in  which  they  are  to  be  preserved. 
Small  larvae,  to  be  preserved  in  alcohol  or  mounted  on  slides,  may 
be  placed  directly  in  the  alcohol-glycerin  solution,  as  indicated 
above.  The  larger  forms,  which  are  to  be  blown  (see  page  353), 
should  be  placed  in  tin  boxes,  together  with  a  small  amount  of 
their  food  plant.  Aquatic  forms  which  it  is  desirous  to  keep  alive 
must  be  packed  in  damp  moss  or  damp  paper,  or  else  carried  in 
a  large,  open  receptacle  filled  with  water.  If  placed  in  a  bottle  or 
tightly  closed  receptacle,  they  will  soon  die.  One  danger  of  carry- 
ing aquatic  larvae  or  nymphs  in  water  is  that  the  larger  forms  will 
often  destroy  the  smaller  ones,  especially  if  dragon-fly  nymphs 
have  been  collected.  There  is  much  less  liability  of  this  occurring 
if  the  nymphs  are  packed  in  wet  moss  or  paper. 

Insect  traps.  Many  insects  can  be  collected  much  more  easily  by 
means  of  traps  than  in  any  other  way.  These  traps  may  consist 
of  some  form  of  light  for  attracting  insects,  some  attractive  food 
from  which  the  insects  may  be  collected  as  they  come  to  it,  or 
a  trap  that  the  insects  will  fall  into. 

The  funnel  trap.  The  ordinary  glass  or  tin  funnel  is  fre- 
quently employed  in  trapping  insects.    One  of  the  simplest  ways 


340 


ELEMENTARY  ENTOMOLOGY 


of  using  this  is  to  fit  a  cyanide  or  alcohol  bottle  over  the  lower 
end  of  the  funnel,  and  sink  the  bottle  and  funnel  in  the  ground 
level  with  the  surface.  This  is  particularly  useful  along  the  coast 
or  in  sandy  localities  where  ground  beetles  are  numerous.  This  will 
prove  more  effective  for  carrion  beetles  if  a  dead  fish,  mouse,  or 
piece  of  meat  is  strung  on  a  wire  and  laid  across  the  funnel.  The 
funnel  is  also  used  in  collecting  very  small  insects,  like  Thysanura. 
The  simplest  method  is  to  take  an  ordinary  glass  funnel,  from 
twelve  to  twenty-four  inches  in  diameter,  and  place  a  cork  stopper 
in  the  lower  end  of  the  neck.  The  neck  is 
to  be  partly  filled  with  alcohol.  The  funnel 
should  then  be  placed  in  a  basin  with 
straight  sides,  which  is  partly  filled  with 
water.  The  basin  may  be  of  tin  or  granite 
ware,  of  slightly  smaller  diameter  than 
the  top  of  the  funnel,  but  deep  enough  so 
that  the  neck  of  the  funnel  does  not  rest 
on  the  bottom.  If  the  funnel  is  not  heavy 
enough  to  prevent  floating,  it  may  be  held 
in  position  by  strips  of  lead  laid  across  the 
top.  This  apparatus  should  then  be  placed 
over  a  gas  flame  or  some  other  even  heat, 
and  the  temperature  of  the  water  raised 
to  between  sixty  and  one  hundred  degrees. 
Since  alcohol  evaporates  so  rapidly,  it 
should  not  be  placed  in  the  funnel  until 
the  apparatus  is  ready  for  use.  The  mate- 
rial containing  the  insects,  such  as  leaves, 
decayed  wood,  etc.,  is  next  placed  in  a  sieve,  the  diameter  of  which 
is  slightly  smaller  than  that  of  the  funnel.  The  sieve  is  then 
placed  over  the  top  of  the  funnel,  and  the  insects,  attracted  by  the 
heat,  rapidly  work  their  way  through  the  material  and  drop  down 
into  the  funnel.  The  insects  are  removed  from  the  funnel  by  taking 
out  the  cork  stopper  and  allowing  the  alcohol  to  run  out  into  a  bottle. 
A  very  convenient  time  to  collect  these  small  insects  is  during  the 
early  fall  or  winter.  Cotton-cloth  bags  may  be  used  to  gather  up 
the  decaying  leaves,  wood,  etc.,  which  are  then  brought  to  the 
laboratory  and  the  insects  sorted  out. 


Fig. 


476.      A    simple    trap 
lantern 


METHODS  OF  COLLECTING  INSECTS 


541 


Many  insects  can  be  secured  in  the  fall  by  providing  suitable 
places  in  which  they  may  hibernate,  such  as  boards,  old  gunny 
sacks,  etc.  placed  on  the  ground.  Another  method  is  to  place 
strips  of  cloth  or  gimny  sacks  around  the  tmnks  of  trees,  and 
examine  them  frequently  for  insects. 

LigJit  traps.  Numerous  forms  of  traps  have  been  constructed, 
to  take  advantage  of  the  habit  of  some  insects  of  flying  toward  the 
light.  One  of  the  simplest  of  these 
traps  (Fig.  476)  is  made  by  placing 
an  ordinar}'  lantern  in  a  shallow 
pan  eighteen  or  twenty  inches  in 
diameter  and  four  inches  deep. 
This  apparatus  is  then  placed  on 
a  stump,  fence  post,  or  other  con- 
spicuous locality.  The  lantern  is 
then  lighted,  and  an  inch  or  two 
of  water,  covered  with  a  film  of 
kerosene,  is  placed  in  the  pan. 
Leave  the  trap  overnight  (the 
darker  the  better)  and  in  the  morn- 
ing remove  the  insects  and  place 
them  in  gasoline  or  benzine  for  a 
short  time,  to  remove  the  kero- 
sene. Thev  can  then  be  laid  on 
blotting  paper,  dried,  and  mounted 
in  the  usual  way. 

Another  method  of  using  the 
trap  lantern  is  to  suspend  a  lantern 
above  a  large  tin  funnel  with  a 
diameter  of  twent}'  or  twenty-four 
inches.  At  the  bottom  of  the  funnel  is  placed  a  cyanide  bottle. 
The  insects,  particularly  beetles,  fly  against  the  light  and  fall  into 
the  funnel  and,  the  sides  being  smooth,  roll  down  into  the  cyanide 
bottle,  ©ther  more  elaborate  arrangements  may  be  fitted  up,  but 
either  of  the  above  forms  will  do  for  most  cases. 

Baiting  insects.  This  form  of  collecting  is  used  principally 
in  capturing  moths  and  other  insects  that  have  a  fondness  for 
sweets.    As  usually  practiced,  the  entomologist  goes  out  just  at 


Svrvs. 

Fig.  477.    The  Gillette  trap  light 

A  lantern  is  hung  over  the  mouth  of  the 
funnel 


342 


ELEMENTARY  ENTOMOLOGY 


twilight  with  a  mixture  of  sugar  and  rum,  sugar  and  vinegar,  or 
some  such  substance,  which  is  painted  on  the  trunks  of  trees.  After 
an  hour  or  so  the  trees  are  visited  by  the  entomologist,  who  is  armed 
with  a  dark  lantern  or  a  bicycle  lantern.  The  moths  are  caught 
either  by  means  of  a  net  or  by  carefully  approaching  the  tree  and 
placing  a  large-mouthed  cyanide  bottle  over  the  insects  as  they  feed. 
Warm,  cloudy  nights  are  best  for  this  work,  although  one  is  not 
always  assured  of  success. 

If  pieces  of  decaying  fish,  meat,  or  other  animal  matter  are 
placed  in  a  convenient  locality  and  examined  from  time  to  time, 
large  numbers  of  beetles  may  be  collected. 


CHAPTER  XXIV 

METHODS   OF  PRESERVING  AND  STUDYING  INSECTS 

The  work  of  the  entomologist  is  only  just  begun  when  the  insects 
are  collected.  They  must  then  be  pinned,  dried,  and  labeled,  the 
latter  mcluding  the  identification,  which  in  itself  is  no  little  matter. 

Mounting  insects.  Insects  should  be  mounted  as  soon  as  pos- 
sible after  being  killed.  When  it  is  impossible  to  mount  them 
immediately,  put  the  insects  in  shallow  pill  boxes  packed  in  tis- 
sue paper,  and  set  in  a  warm  place  to  dry.  When  ready  to  mount, 
remove  the  lid  and  place  the  box  in  a  tight  glass  jar,  together  with 
a  sponge  dipped  in  camphor  water.  The  insects  should  be  left  in 
this  chamber  for  from  24  to  48  hours,  when  they  can  be  mounted 
as  usual. 

Insects  should  be  mounted  on  insect  pins.  These  are  made 
especially  for  the  purpose,  are  about  an  inch  and  a  half  in  length, 
and  range  in  size  from  No.  000,  the  most  slender,  up  to  No.  8, 
which  is  the  largest.    Nos.  i,  2,  and  3,  however,  will  do  for  nearly 


Fig.  478.    Pinning  forceps 

all  purposes,  with  a  few  of  No.  5  for  the  larger  moths.  No.  3  is 
large  enough  for  almost  all  larger  insects,  and  insects  too  small  for 
No.  I  should  be  mounted  on  points.  The  pins  may  be  obtained 
in  either  the  black  japanned  or  the  plain  white  metal ;  the  latter, 
however,  should  be  used  only  in  mounting  insects  on  points,  as  a 
green  verdigris  is  produced  near  the  insect,  which  corrodes  the  pin. 
The  collector  should  be  careful  to  have  all  the  insects  at  the 
same  distance  from  the  head  of  the  pin  ;  this  not  only  makes  the 

343 


344 


ELEMENTARY  ENTOMOLOGY 


collection  look  better,  but  also  makes  it  much  easier  to  handle  and 
study.  The  general  rule  followed  by  entomologists  is  that  one  fourth 
of  the  pin  shall  project  above  the  insect.  For  this  purpose  a  pinning 
block  is  almost  indispensable,  the  construction  of  which  will  be 
readily  understood  by  referring  to  Fig.  479.  The  lower  hole  should 
be  one  fourth  the  length  of  the  pin  in  depth,  the  second,  one  half 
the  length,  and  the  third,  three  fourths  the  length.  After  the  pin 
has  been  pushed  through  the  insect,  the  head  is  inserted  in  the 
lower  hole  and  the  insect  pushed  down  until  the  back  touches  the 
block.  The  second  hole  is  for  evening  up  the  labels,  and  the  third 
one  for  placing  points  on  the  pins. 

A  great  deal  of  skill  is  required  in  pinning  insects  properly. 
The  specimen  should  be  grasped  by  the  thumb  and  forefinger 


Fig.  479.    A  pinning  block 

and  held  very  lightly  in  the  groove  formed  between  the  tips  of  the 
thumb  and  forefinger  while  the  pin  is  inserted  in  the  proper  place. 
Another  method  is  to  place  the  insects  on  some  soft  substance,  as 
a  folded  handkerchief,  and  turning  the  insect  ventral  side  down, 
insert  the  pin,  finishing  the  operation  on  the  pinning  block. 

Since  the  different  groups  of  insects  present  certain  structural 
peculiarities,  the  following  system  of  pinning  the  members  of 
different  orders  has  gradually  been  formed.  (The  directions  for 
mounting  on  points  and  slides  are  given  below.) 

Thysanura  and  CoUembola.  All  of  the  smaller  species  are 
mounted  on  microscope  slides  ;  the  larger  forms  are  pinned  through 
the  metathorax.  A  very  fine  wire  is  run  entirely  through  the  body, 
to  serve  as  a  support.  In  the  case  of  the  Thysanura,  this  should 
be  inserted  just  underneath  the  long,  median  setae  and  run  forward 
well  into  the  thorax.  If  the  end  is  left  projecting,  it  may  be  made 
to  serve  as  a  support  for  the  posterior  setae. 


PRESERVING  AND  STUDYING  INSECTS 


345 


May-flies,  dragon -flies,  and  stone-flies.  The  pin  is  inserted  in 
the  metathorax,  and  a  fine  wire  run  from  the  end  of  the  body 
into  the  thorax.  In  the  case  of  the  May-flies  this  wire  should  be 
left  projecting  to  serve  as  a  support  for  the  posterior  setas,  which 
should  be  attached  to  the  wire.  The  wings  of  both  the  May-flies 
and  dragon-flies  should  be  spread.  This  is  done  by  means  of  a 
spreading  board. 

Spreading  boards.  Fig.  480  shows  the  construction  of  a  simple 
spreading  board.  Two  soft-pine  boards  are  placed  parallel  on  short 
crosspieces,  the  boards  being 
at  a  slight  angle  to  each  other. 
The  edges  of  the  board  should 
be  from  one  sixteenth  to  one 
half  an  inch  apart,  depending 
on  the  size  of  the  insects  to  be 
mounted.  A  thin  sheet  of  cork 
is  glued  to  the  underside  of 
the  boards.  When  the  spread- 
ing board  is  used,  the  insect 
is  pinned  in  the  ordinary  man- 
ner and  the  pin  is  then  forced 
through  the  sheet  of  cork  until 
the  dorsal  portion  of  the  insect 
is  nearly  level  with  the  upper 
surface  of  the  boards.  The 
spreading  board,  of  course, 
must  be  selected  with  a  groove 
wide  enough  to  accommodate  the  body  of  the  insect.  After  being 
placed  on  the  spreading  board,  the  wings  of  the  insect  are  brought 
forward  and  held  in  position  by  narrow  strips  of  paper  or  tracing 
cloth,  as  shown  in  the  illustration.  Glass-headed  pins  are  handy 
for  pinning  the  strips.  The  spreading  board  is  then  set  away  until 
the  insect  is  thoroughly  dry. 

In  the  case  of  the  May-flies  the  front  margins  of  the  first  pair  of 
wings  are  brought  forward  until  they  are  at  right  angles  with  the 
body.  In  the  case  of  the  dragon-flies  the  hind  margins  of  the  first 
pair  of  wings  should  be  at  right  angles  to  the  body.  In  pinning 
stone-flies,  usually  only  the  wings  of  the  right  side  are  spread, 


Fig.    4S0.     Board    showinc 
spreading  Lepidoptera. 


method    of 
(Reduced) 


346 


ELEMENTARY  ENTOMOLOGY 


Fig.  481.    Showing  method  of  pinning 
Orthoptera 

(After  Washburn) 


although  some  entomologists  spread  the  wings  on  both  sides.  The 
front  margins  of  the  hind  pair  of  wings  should  be  at  right  angles 
to  the  body,  the  front  pair  being  brought  forward  until  they  just 
touch  the  hind  pair. 

Platyptera.  White  ants  are  usually  mounted  in  alcohol,  or  on 
microscope  slides,  although  the  winged  forms  may  be  pinned 
through  the  metathorax.  The  wings  are  seldom  spread.  Book- 
lice  are  mounted  either  on  points 
or  on  microscope  slides,  while 
bird-lice  are  invariably  mounted 
on  microscope  slides.  Earwigs 
are  mounted  on  points,  or,  in  the 
larger  forms,  the  pin  is  inserted 
through  the  anterior  portion  of 
the  right  wing-cover. 

Orthoptera  (Fig.  481).  In  the 
ordinaiy  grasshopper,  and  in 
those  forms  having  the  prono- 
tum  well  developed,  the  pin  is 
usually  inserted  through  the  posterior  margin  of  the  pronotum. 
In  forms  in  which  the  pronotum  is  not  well  developed  the  pin  is 
run  through  the  metathorax.  The  wings  may  or  may  not  be 
spread,  but  the  usual  method  is  to  spread  the  wings  on  the  right 
side  of  the  body.  Care  should  be  taken  to  arrange  the  legs  and 
antennae,  the  latter  being  laid  back  over  the  body, 
if  possible.  The  legs  may  be  held  in  position  by 
running  the  pin  through  a  square  of  stiff  paper, 
which  is  brought  up  to  the  proper  distance  and 
the  legs  kept  in  a  natural  position  until  dry. 

Hemiptera  (Fig.  482).  All  of  the  larger  He- 
miptera  are  pinned  through  the  metathorax  ;  the 
smaller  forms,  with  the  exception  of  the  Aphididae 
and  scale  insects,  are  mounted  on  points.  The  two 
latter  groups  require  special  methods  of  mounting. 
The  Aphididae  are  frequently  mounted  by  plac- 
ing them  on  a  glass  slide  and  covering  them  with  a  drop  of  Canada 
balsam  dissolved  in  xylol.  They  are  allowed  to  stand  for  twenty- 
four  hours,  when  a  small  amount  of  fresh  balsam  is  applied,  and 


Fig.  482.  Showing 

method  of  pinning 

Hemiptera 

(After  Washburn) 


PRESERVING  AND  STUDYING  INSBXTS  347 

the  specimens  covered  with  a  cover  glass.  This  method  is  far 
from  satisfactory,  as  the  balsam  soon  clouds,  but  at  present  it  is 
the  only  thing  that  can  be  recommended  as  a  permanent  mount. 

Two  methods  are  employed  in  mounting  scale  insects.  The 
entire  scales  are  mounted  by  taking  a  thin  strip  of  bark  on  which 
is  found  a  colony  of  scales,  and  after  leaving  it  in  the  cyanide 
bottle  for  twenty-four  hours,  it  is  placed  between  two  pieces  of 
celluloid.  The  two  plates  of  celluloid  are  held  apart  by  a  cell  cut 
out  of  cardboard,  and  the  entire  mount  sealed  with  passe-partout 
tape.  The  thickness  of  the  cell  depends  upon  the  thickness  of  the 
piece  of  bark  to  be  mounted.  It  will  be  found  very  convenient  to 
have  these  cells  cut  the  size  of  an  ordinary  microscope  slide.  This 
form  of  mounting  \\\\\  do  only  for  very  superficial  study,  and  some 
of  the  scales  must  be  cleared  and  mounted  in  balsam.  This  is 
done  by  removing  the  scales  from  the  bark  and,  in  the  case  of  the 
armored  or  flat  scales,  removing  the  insects  from  under  the  scales 
and  placing  them  in  a  small  test  tube  with  caustic  potash  solution. 
These  should  be  boiled  until  clear,  the  length  of  time  depending 
upon  the  thickness  of  the  scales.  They  are  then  washed  in  water 
by  sedimentation  ;  that  is,  the  test  tube  is  filled  with  water  and 
held  in  a  vertical  position  until  the  scales  have  settled  to  the  bot- 
tom. The  water  is  then  nearly  all  drawn  off  with  a  pipette,  and  the 
process  is  repeated.  After  all  of  the  caustic  potash  has  been  re- 
moved, they  are  washed  in  95  per  cent  alcohol  and  cleared  in 
xylol.  They  should  then  be  removed  to  a  glass  slide  by  means  of 
a  camel's-hair  brush,  and  mounted  in  balsam.  Since  the  last  seg- 
ment of  the  abdomen,  the  pygidium,  is  the  only  part  of  the  insect 
used  in  classification,  this  is  all  that  it  is  necessary  to  mount, 

Neuroptera,  Mecoptera,  and  Tricoptera.  These  forms  are  all 
pinned  through  the  metathorax  ;  the  wings  may  or  may  not  be 
spread,  but  it  is  usually  best  to  spread  the  wings  at  least  on  one 
side  of  the  body,  the  hind  borders  of  the  front  pair  of  wings  being 
brought  forward  at  right  angles  to  the  body. 

Lepidoptera  (Fig.  480).  In  mounting  Lepidoptera  the  pin  is  run 
through  the  mesothorax  or  metathorax ;  the  wings  are  always  spread, 
the  front  pair  being  brought  forward  until  the  hind  margins  are  at 
right  angles  to  the  body.  This  rule  is  invariably  followed  both 
with  the  moths  and  butterflies.    The  smaller  forms  are  usually 


348 


ELEMENTARY  ENTOMOLOGY 


Fig.  483.   Showing 

method  of  pinning 

Coleoptera 

(After  Washbum) 


mounted  on  elbow  pins,  or  on  bits  of  fine  silver  wire  {ininntic7i- 
nadeln),  which  are  stuck  through  bits  of  cork  or  pith  and  pinned 
like  a  cardboard  point. 

Diptera.  In  the  Diptera  the  pin  is  run  through  the  central  part 
of  the  thorax,  and  the  wings,  if  not  spread,  should  be  extended. 
In  the  long-legged  flies,  as  the  crane-fly,  the 
legs  should  be  supported  until  the  specimen 
is  dry.  In  fact,  it  is  not  a  bad  idea  to  place  a 
permanent  piece  of  cardboard  on  the  pins  hold- 
ing such  specimens.  The  smaller  Diptera  are 
usually  mounted  on  wire  or  cardboard  points. 

Coleoptera  (Fig.  483).  All  of  the  larger  Cole- 
optera are  pinned  through  the  anterior  inner 
portion  of  the  right  wing-cover. 
The  wings  are  never  spread, 
and  but  little  attention  need  be 
given  the  specimens  after  pin- 
ning, as  the  legs  usually  adjust 
themselves.  The  smaller  forms 
are  mounted  on  cardboard  points  and  should  be 
glued  on  the  side  to  reveal  the  undersurface. 

Hymenoptera  (Fig.  484).  These  are  pinned 
through  the  metathorax  ;  the  wings  may  or  may 
not  be  spread.  Some  of  the  more  slender  forms, 
as  the  Ichneumon-flies,  require  a  support  until 
they  are  dry.  Many  of  the  parasitic  Hymenoptera 
are  mounted  on  slides  in  Canada  balsam,  but  the  usual  way  is  to 

mount  on  points, 
either  cardboard  or 
wire. 

Mounting  insects 
on  points.  General 
directions  have  al- 
ready been  given 
for  mounting  insects  on  points.  It  may  be  well,  however,  to  men- 
tion some  of  the  different  types  of  points  used  in  mounting  insects. 
Micro-pins  (Fig.  486,  d)  are  largely  used  for  mounting  Lepidoptera, 
Neuroptera,    and    Diptera.     These    micro-pins   {niijiutien-iiadchi) 


Fig.  484.  Showing 

method  of  pinning 

Hymenoptera 

(.\fter  Washbum) 


Fig.  485.    Point  punch 


PRESERVING  AND  STUDYING  INSECTS 


349 


consist  of  very  fine  pieces  of  steel  wire,  and  may  be  run  through 
narrow  strips  of  cork,  pieces  of  paper,  or  small  squares  of  cork,  as 
shown  in  Fig.  486,  /;,  <■/,  and  c.  Elbow  pins  (Fig.  486,  c)  present 
a  neater  appearance  than  the  micro-pins,  and  may  be  obtained  of 
entomological  supply  companies. 


4^x^. 


V 


^7 


^ 


\ 


d  c  </  e 

Fig.  486.    Method  of  mounting  insects  on  points 


/ 


(7,  with  a  cardboard  point ;   b,  micro-pin  in  cork ;   c,  elbow  pin  :   </,  micro-pin  in  paper  ; 
e,  micro-pin  in  side  ;  /,  double  point.    (After  Banks) 

Most  small  Hemiptera  and  Coleoptera  (Fig.  487)  are  mounted 
on  small,  triangular  points  cut  from  light  Bristol  board.  Punches 
(Fig,  485)  may  be  secured  to  cut  these  points  accurately. 

In  mounting,  the  point  is  first  placed  on  the  pin  at  the  required 
height.  The  end  of  the  point  is  next  dipped  in  gum  shellac  dis- 
solved in  alcohol  and  then  touched  to  the  ventral  side  of  the  insect. 
The  insect  will  adhere  to  the  point,  and 
should  be  arranged  in  position  with  fine 
needles  and  forceps.  The  insect  is  mounted 
so  that  when  the  point  is  directed  to  the 
left,  the  head  of  the  insect  is  away  from 
the  person.  For  insects  having  long  bodies 
a  double  point  should  be  used,  as  shown 
in  Fig.  486,/. 

Whether  micro-pins  or  points  are  used, 
care  should  be  taken  not  to  obscure  more 
of  the  insect  than  is  absolutely  necessary. 

Labeling.  All  specimens  should  be  labeled  as  soon  as  possible 
after  pinning.  The  label  should  consist  of  the  name  of  the  town 
and  state,  on  the  first  line,  and  the  date  of  collecting,   on  the 


Fig.  4S7.    Method  of  glu- 
ing beetle  on  paper  point 

(After  Banks) 


350         ELEMENTARY  ENTOMOLOGY 

second  line  ;  some  entomologists  have  the  name  of  the  collector 
on  the  third  line.  These  labels  should  be  printed  in  diamond  type 
on  the  best  paper  procurable,  and  may  be  had  for  from  twenty-five 
to  thirty  cents  a  thousand.  In  having  labels  printed,  the  space  for 
the  date  should  be  left  blank,  to  be  filled  in  later.  Only  the  best 
India  ink  and  very  fine  crow-quill  pens  should  be  used.  Below 
the  locality  label  should  be  the  accession  number,  the  collection 
being  numbered  serially  and  each  insect  given  a  separate  number, 
unless  two  or  more  of  the  same  species  were  collected  under 
the  same  conditions.  The  accession  number  should  refer  to  the 
collector's  notes,  in  which  ever)'thing  known  about  the  insect  is 
recorded.  The  date  and  place  of  collecting  should  again  be  re- 
corded and  the  food  plant  or  nature  of  the  locality  where  the 
insect  was  found,  etc. 

Arrangement  of  insects.  For  the  permanent  storage  of  insect 
collections  two  general  types  of  box  are  used.  One  consists  of 
large  glass-top  drawers,  about  fifteen  by  eighteen  inches,  which  fit 
into  cabinets.  The  other  type  consists  of  separate  boxes,  with  cork 
bottoms.  For  the  beginner  the  latter  type  is  probably  the  better. 
Numerous  boxes  are  on  the  market,  made  from  both  cardboard 
and  wood,  the  latter,  of  course,  being  far  superior  to  the  cardboard. 

In  selecting  insect  boxes  care  must  be  taken  to  obtain  those 
having  tight-fitting  lids.  This  is  absolutely  essential  in  order  to 
keep  out  certain  Dermestid  beetles,  which,  if  they  gain  access  to  the 
collection,  will  quickly  destroy  it.  Further  precaution  against  these 
insects  should  be  taken  by  placing  flake  naphthalene  in  the  boxes. 
By  far  the  best  on  the  market  is  the  Schmitt  box  (Fig.  488). 
This  comes  in  two  sizes,  twelve  by  fifteen  inches  and  eight  and 
one  half  by  fifteen  inches,  and  is  lined  with  pressed  cork.  In  using 
the  drawers,  the  insect  pins  are  stuck  into  small  blocks  of  wood, 
or  into  a  lining  of  sheet  cork,  by  means  of  pinning  forceps  (Fig. 
478).  The  blocks  ^  are  cut  to  a  uniform  length  and  are  made  in 
multiple  width.  The  width  of  the  blocks  used  depends  on  the  size 
of  the  insects  and  the  number  of  specimens  of  each  species.  The 
advantage  of  this  system  is  that  it  allows  an  indefinite  amount  of 
expansion  of  a  collection,  without  necessitating  the  transfer  of  each 
individual  insect. 

^  See  Comstock's  "Insect  Life." 


PRESERVING  AND  STUDYING  INSECTS 


;5i 


Whether  the  boxes  or  drawers  are  used,  all  of  the  specimens 
of  one  species  should  be  kept  together,  which  plan  should  be 
followed  out  in  genera,  families,  and  orders. 


Fig.  488.    A  Schmitt  insect  box,  opened  to  show  arrangement  of  insects 
(After  Banks) 

Mounting  insects  on  slides.  Directions  have  already  been  given 
for  the  mounting  of  aphides  and  scale  insects.  The  directions 
given  for  mounting  scale  insects  may  be  used  for  mounting  legs 


352 


ELEMENTARY  ENTOMOLOGY 


or  other  hard  parts  of  insects,  where  nothing  but  the  chitinous 
portion  is  desired.  For  most  purposes,  however,  such  as  mount- 
ing the  legs  of  bees  for  laboratory  use,  or  mounting  small, 
hard-bodied  insects,  the  following  method  will  be  found  more 
desirable. 

The  insect  or  part  of  the  insect  to  be  mounted  should  first  be 
placed  in  85  per  cent  alcohol.  This  rule  applies  to  mounting  both 
fresh  specimens  and  material  previously  preserved  in  alcohol  or 
glycerin.  After  the  insect  has  become  thoroughly  saturated,  it 
should  be  transferred  to  95  per  cent  alcohol  and  left  for  an  hour 
or  longer.  The  specimens  should  then  be  transferred  to  xylol  and 
left  until  the  alcohol  is  entirely  replaced.  The  insect  should  then 
be  placed  in  the  center  of  the  slide,  the  excess  of  xylol  removed 
with  a  piece  of  blotting  paper,  and  a  drop  of  Canada  balsam  placed 
over  the  insect.  The  balsam  should  then  be  warmed  slightly  over 
an  alcohol  lamp,  and  a  cover  glass  placed  over  it.  Care  must  be 
taken  not  to  get  on  more  balsam  than  is  necessary  to  cover  the 
insect  and  fill  out  the  space  under  the  cover  glass.  For  the  be- 
ginner there  is  less  liability  of  having  air  bubbles  in  the  mount  if 
the  balsam  is  first  placed  on  the  slide  and  the  insect  laid  on  after- 
wards. However,  it  is  much  more  difficult  to  arrange  the  wings 
and  legs  of  the  insect  if  mounted  in  this  way. 

Preserving  material  in  liquids.  Directions  have  already  been 
given  for  collecting  small,  soft-bodied  insects  in  liquid.  When  this 
material  is  first  brought  into  the  laboratory,  it  should  be  thoroughly 
washed  in  50  per  cent  alcohol  and  then  transferred  to  85  per  cent 
alcohol.  If  the  specimens  are  large,  soft-bodied  larvae,  or  insects 
of  considerable  size,  the  alcohol  should  be  changed  at  least  once 
before  permanently  storing  the  specimens.  For  permanently 
storing  alcoholic  material  small,  straight-necked  vials  will  be  found 
the  most  convenient.  These  should  be  of  one-,  two-,  and  four- 
dram  sizes  and  fitted  with  the  best  cork  stoppers  procurable.  The 
bottles  should  be  numbered  and  labeled  as  in  pinned  insects,  the 
labels  being  written  on  strips  of  good  linen  paper  in  India  ink, 
which  must  be  absolutely  waterproof.  These  should  be  placed 
inside  the  bottles  with  the  specimens.  Numerous  trays  have  been 
devised  for  holding  alcoholic  material,  the  one  shown  in  Fig.  489 
being  very  satisfactory.    An  improvement  of  this  tray  consists  in 


PRESERVING  AND  STUDYING  INSECTS 


353 


having  either  end  extend  up  above  the  top  of  the  bottles.  This 
allows  the  trays  to  be  stacked  one  above  another  without  injuring 
the  bottles. 

Numerous  substitutes  for  alcohol  have  been  employed,  of  which 
a  4  per  cent  solution  of  formaldehyde  is  probably  the  best,  as  it 
is  cheaper,  tends  to  preserve  the  color,  and  does  not  harden  the 


Fig.  489.    The  Marx  tray  for  specimens  in  liquid 

specimens.    This,  however,  is  not  much  superior  to  alcohol,  and 
in  many  cases  shrinks  the  specimens  more  than  alcohol  would. 

Material  intended  for  dissection  may  be  treated  as  above,  but 
if  alcohol  is  used,  should  be  permanently  preserved  in  70  to  85 
per  cent  alcohol,  to  which  10  percent  of  glycerin  has  been  added. 

Inflating  insect  larvae.  The  larvae  of  most  of  the  Diptera, 
Coleoptera,  and  Hymenoptera  are  preserved  in  alcohol,  as  noted 
above.  It  has  been  found,  however, 
that  lepidopterous  larvae  may  be* 
preserved  much  better  by  inflating 
them,  the  method  of  which  is  as 
follows  : 

The  lar\'^  are  brought  to  the 
laboratory  alive,  and  when  ready  to 
be  inflated  are  killed  or  stupefied  in 
a  cyanide  bottle.  This  method  will 
be  found  much  better  than  killing 
the  larvae  in  the  field,  as  they  should 
be  blown  as  soon  as  possible  after 
they  are  killed.  Remove  the  larva  from  the  cyanide  bottle  and 
place  it  on  a  piece  of  blotting  paper.  A  glass  tube  or  pencil  is 
next  rolled  over  the  body  from  the  head  toward  the  tip  of  the 
abdomen.  This  causes  the  alimentary  tract  to  protrude,  which  is 
then  snipped  off  at  the  anus  by  a  pair  of  sharp-pointed  scissors. 


Fig.   490.     Homemade    apparatus 
for  inflating  larvae 

(After  Washburn) 


354 


ELEMENTARY  ENTOMOLOGY 


Fig.  491.    Method  of  mounting  inflated  larvae 
(After  Washburn) 


The  rolling  is  then  continued  until  the  entire  contents  of  the  body 
have  been  forced  out  through  the  posterior  end.  A  straw  or  a 
glass  tube  which  has  been  drawn  out  to  a  fine  point  is  next  in- 

9  serted  through  the  'open- 
ing. This  may  in  turn  be 
attached  to  a  rubber  tube 
and  bulb,  or  the  larva 
may  be  inflated  by  blow- 
ing gently  through  the 
tube.  In  order  to  keep 
the  specimen  on  the  end 
of  the  tube,  it  should  be 
allowed  to  dry  for  a  few 
minutes.  To  thoroughly  dry  the  skin  it  is  kept  distended  inside  a 
glass  lamp  chimney,  which  rests  in  a  pan  of  sand  over  a  gas  or 
alcohol  flame,  as  shown  in  Fig.  490.  When  the  skin  is  thor- 
oughly dried,  it  is  removed  from  the  glass  tube  and  may  then  be 
mounted  on  an  elbow  pin  by  bending  the  point  of  the  elbow  into 
a  loop,  which  is  dipped  into  glue  and  inserted  into  the  opening  in 
the  abdomen.    Another  method  is  shown  in  Fig.  491. 

Dissecting  instruments.  The  number  of 
different  instruments  required  for  the  study  of 
the  anatomy  of  insects  is  not  great.  However, 
owing  to  the  small  size  of  the  specimens 
studied,  the  instruments  should  be  of  the  very 
best  material. 

Forceps.  Forceps  should  be  of  two  kinds, 
curved-pointed  and  straight-pointed  (Fig.  492). 
Both  pairs  should  have  very  fine  points  which 
are  slightly  roughened. 

Scissors.  Curved  scissors  will  be  found  very 
useful  in  carrying  on  minute  dissecting  work, 
the  difficulty  being  to  secure  a  pair  that  will 
cut  entirely  to  the  point.  In  using  the  fine- 
pointed  scissors,  care  must  be  exercised  not 
to  strain  them  by  cutting  too  thick  objects. 

Scalpels.    These  are  of  less  importance  in      LTved^poin^eTand 
entomological  work  than  in  most  other  forms         straight-pointed 


PRESERVING  AND  STUDYING  INSECTS  355 

of  dissecting,  but  two  or  three  scalpels  of  various  shapes  will 
be  found  useful.  The  short,  curved,  sickle-shaped  scalpel  will  be 
used  in  general  dissection  more  than  any  other. 

Needles.  These  are  really  of  more  impoitance  than  the  scalpel. 
They  may  be  made  by  forcing  the  eye  of  an  ordinary  needle  into 
a  small  stick  about  the  size  of  a  lead  pencil.  Much  more  satisfac- 
tory needle  handles  may  be  secured  of  the  supply  companies,  with 
arrangements  for  removing  and  exchanging  the  needle.  One  should 
be  provided  with  three  of  four  of  these  needle  holders  and  a  num- 
ber of  needles  bent  into  various  shapes,  —  hooks  of  different 
sizes,  and  curved  and  straight  needles. 

Brushes.  An  assortment  of  camel's-hair  brushes  will  be  found 
useful  on  the  dissecting  table. 

Pius.  For  holding  the  dissected  specimens  in  position  ordinary 
insect  pins  will  be  found  most  convenient.  The  larger  sizes, 
Nos.  4,  6,  and  8,  are  well  adapted  for  minute  dissection.  A  few 
large  pins  with  black  glass  heads  will  also  be  found  useful  for 
heavier  work. 

Microscopes  and  lenses.  Every  collector  should  be  provided  with 
at  least  one  good  pocket  lens.  For  most  work  a  half-inch  lens, 
procurable  of  any  microscope  supply  company,  will  be  found  suf- 
ficient. For  very  small  insects,  however,  a  one-fourth-inch  lens 
will  be  found  much  better. 

Dissecting  microscopes  are  almost  an  essential  if  careful  work  in 
insect  anatomy  is  to  be  done.  Various  types  of  these  are  sold  by 
all  optical  companies.  Compound  microscopes  are  essential  for  very 
minute  work,  but  for  studying  the  general  anatomy  of  insects  they 
can  be  more  easily  dispensed  with  than  the  dissecting  microscope. 

Dissecting  trays.  Dissecting  trays,  as  found  on  the  market,  con- 
sist of  shallow  tin  or  porcelain  trays  ranging  in  size  from  four  by  five 
to  twelve  by  fifteen  inches,  with  a  depth  of  from  one  to  three  inches. 
The  bottoms  of  these  trays  are  usually  covered  with  paraffin  or  bees- 
wax, so  that  the  specimens  may  be  pinned  out  under  water.  Home- 
made trays  may  be  constructed  by  obtaining  tin  pans  of  the  proper 
size,  and  having  two  or  three  short  pieces  of  wire  soldered  to  the 
bottom.  The  ends  of  the  wire  should  be  left  projecting,  so  that 
when  hot  paraffin  or  beeswax  is  poured  into  the  pan,  the  wire  will 
hold  it  firmly  in  place  and  prevent  it  from  floating  when  in  use. 


356 


ELEMENTARY  ENTOMOLOGY 


This  sort  of  dissecting  tray  works  very  well  for  rough  dissection, 
where  nothing  more  than  a  hand  lens  is  required.  It  has  the 
objection,  however,  of  the  projecting  sides,  which  frequently  pre- 
vent one  from  manipulating  the  dissecting  instruments  as  desired. 
By  far  the  most  successful  dissecting  tray  for  insect  work  that  we 
have  used  is  made  as  follows  :  A  glass  plate  four  by  five  inches  is 
thoroughly  washed  in  alcohol  in  order  to  remove  all  traces  of  dirt. 
This  is  then  placed  in  a  shallow  pan  which  has  been  previously 
coated  with  vaseline  or  oil.    A  mixture  of  four  parts  paraffin  and 

one  part  beeswax  is  next 
poured  over  the  glass 
plate  to  a  depth  of  about 
one  inch.  After  this  is 
thoroughly  cool,  it  is  re- 
moved from  the  pan  and 
the  paraffin  trimmed  off 
to  the  edge  of  the  glass 
plate.  A  trough  is  scraped 
out  in  the  center  of  the 
plate  to  accommodate  the 
body  of  the  insect  to  be 
dissected.  After  a  little 
experience  one  can  very 
quickly  regulate  the  size 
and  shape  of  this  trough 
to  the  best  advantage.  A 
sufficient  amount  of  par- 
affin should  be  left  be- 
neath the  insect  to  permit 
of  its  being  firmly  pinned 
in   position.     The   work 


Fig.  493.   The  Riley  breeding  cage 


will  also  be  greatly  facilitated  if  glycerin,  to  which  an  excess  of 
chloral  hydrate  has  been  added,  is  used  as  a  dissecting  medium  in 
place  of  water.  This  form  of  tray  has  a  number  of  distinct  advan- 
tages. In  the  first  place,  the  work  can  be  carried  on  entirely  with 
the  dissecting  microscope,  or  even  a  low  power  of  the  compound 
microscope.  There  are  no  projecting  sides  to  interfere  with  the 
manipulation    of    the    instruments,   and   if  the  dissection   is   not 


PRESERVING  AND  STUDYING  INSECTS 


\57 


completed,  it  may  be  temporarily  sealed  by  covering  with  a  glass 
plate  which  is  firmly  pressed  in  position.  The  glycerin  has  many 
distinct  advantages  over  water,  its  density 
holding  the  more  delicate  structures  in 
position,  and  at  the  same  time  it  has  a 
higher  index  of  refraction.  Plates  of  vari- 
ous sizes  and  depths  may  be  easily  con- 
structed to  meet  different  requirements. 

Rearing  insects.  If  one  wishes  to  study 
the  life  history  of  insects,  or  if  desirous  of 
procuring  especially  fine  specimens,  by  far 
the  best  method  is  to  rear  them  under 
artificial  conditions.  In  this  work  an  at- 
tempt must  always  be  made  to  simulate 
natural  conditions  as  closely  as  possible. 
There  is  less  liability  of  the  larvae  being 
parasitized  if  they  are  placed  in  a  breed- 
ing cage  when  quite  small.  Numerous 
breeding  cages  have  been  constructed  for 
the  purpose  of  rearing  larvae.     Of  these, 


Fig.  494.   A  lamp-chimney 
breeding  cage 

(After  Banks) 


one    of  the   best   is   shown   in   Fig.   493. 


This  consists  of  a  frame  with  a  glass  door 
on  one  side,  the  other  three  sides  being 
covered  with  cheesecloth.  If  possible,  the 
food  plant  is  placed  in  a  flowerpot  inside 
the  breeding  cage.  If  this  is  impracticable,  twigs  and  branches 
can  be  placed  in  the  cage  in  bottles  of  water,  the  top  of  the  bottle 
being  stuffed  full  of  cotton  to  prevent  the  lar- 
vae from  drowning.  Another  simple  breed- 
ing cage  for  smaller  insects  is  made  by 
placing  a  lantern  globe  or  lamp  chimney, 
the  top  of  which  is  covered  with  a  square  of 
cheesecloth,  over  the  food  plant  (Fig.  494) 
in  a  flowerpot.  The  food  material  should  be 
changed  frequently,  so  that  it  may  be  kept 
fresh  and  sufficient. 

For  rearing  large  quantities  of  larvae  an 
open  tray  three  by  five  feet  is  most  convenient. 


P'iG.  495.   A  simple  aqua- 
rium for  aquatic  larvae 


(After  Washburn) 


358 


ELEMENTARY  ENTOMOLOGY 


The  sides  of  the  tray  are  made  of  Hght  six-inch  boards,  and  the 
bottom  is  formed  by  a  piece  of  cheesecloth.  Four-inch  strips  are 
next  tacked  to  the  top  of  the  tray,  so  that  they  project  inward 
around  it.  The  inside  of  the  projecting  ledge  formed  by  the  four- 
inch  strips  is  coated  with  tanglefoot.  The  food  and  the  larvae  are 
placed  in  the  tray  on  the  cheesecloth.  The  larvae  are  easily  ob- 
served all  the  time,  and  the  food  material  may  be  quickly  changed, 
while  the  tanglefoot  prevents  the  escape  of  the  larvae.  The  larvae, 
however,   are  not  protected  from  parasites,  and  the  pupae  must  be 

removed  and  placed  in 
tight  cages  before  the 
adults  emerge. 

Aquatic  larvae  and 
nymphs  may  be  reared 
in  any  suitable  aquarium 
(Fig.  495),  but  only 
larvae  of  the  same  size 
should  be  kept  together, 
and  care  should  be  taken 
to  separate  those  which 
are  predacious  upon  one 
another. 

Numerous   cages   for  the   study  of  special   insects   have  been 

devised,  as  the  Comstock  root-cage,  devices  for  studying  the  life 

history  of  ants,  the  limb  cage  for  rearing  insects  out  of  doors  in 

their  natural  habitat,  and  the  breeding  cage  for  parasites  (Fig,  496). 

For  further  methods,  consult  the  following  books  : 

L.  O.  Howard,  The  Insect  Book.    (Doubleday,  Page  &  Co.) 
W.  J.  Holland,  The  Moth  Book.    (Doubleday,  Page  &  Co.) 
V.  L.  Kellogg,  American  Insects.    (Henry  Holt  and  Company) 
J.  H.  and  A.  B.  Comstock,  Insect  Life.    (D.  Appleton  &  Co.) 


Fig.  496.    Breeding  cage  for  parasites 
(After  Banks) 


APPENDIX 

r.    DEALERS  IN  ENTOMOLOGICAL  SUPPLIES 

The  American  Entomological  Co.,  55  Stuyvesant  Ave.,  Brooklyn,  N.Y. 

The  Kny-Scheerer  Co.,  404  West  Twenty-seventh  St.,  New  York  City 

The  Entomological  Society  of  Ontario,  Guelph,  Ontario 

M.  Abbott  Frazer,  93  Sudbury  St.,  Boston,  Mass. 

A.  Smith  and  Sons,  269  Pearl  St.,  New  York  City 

Charles  C.  Reidy,  432  Montgomery  St.,  San  Francisco,  Cal. 

The  Simplex  Net  Co.,  Ithaca,  N.Y.    (Nets.) 

Bausch  and  Lomb,  Rochester,  N.Y.    (Microscopes,  lenses,  instruments,  etc.) 

Queen  &  Co.,  loio  Chestnut  St.,  Philadelphia,  Pa.  (Microscopes,  lenses,  instru- 
ments, etc.) 

The  Spencer  Lens  Co.,  Buffalo,  N.Y.    (Microscopes,  lenses,  instruments,  etc.) 

The  Wiegner  Printery,  2234  North  Twenty-ninth  -St.,  Philadelphia,  Pa. 
(Labels.) 

C.  V.  Blackburn,  32  Chestnut  St.,  Stoneham,  Mass.    (Labels.) 


II.    ADDRESSES  OF  STATE  AGRICULTURAL  EXPERIMENT 
STATIONS  AND  OF  STATE  ENTOMOLOGISTS 

Alabama,  Auburn  Iowa,  Ames 

Arizona,  Phoenix  Kansas,  Manhattan 

Arkansas,  Fayetteville  Kentucky,  Lexington 

California,  Berkeley  Louisiana,  Baton  Rouge 

Colorado,  Fort  Collins  Maine,  Orono 

Connecticut,  New  Haven  Maryland,  College  Park 

Delaware,  Newark  Massachusetts,  Amherst 

Florida,  Gainesville  Michigan,  East  Lansing 

Georgia,  State  Entomologist,  Atlanta  Minnesota,  St.  Anthony  Park 

Hawaii,  Honolulu  Mississippi,  Agricultural  College 

Idaho,  Moscow  Missouri,   Columbia 

Illinois,  State  Entomologist,  LIrbana  Montana,  Bozeman 

Indiana,  Lafayette  Nebraska,  Lincoln 

State  Entomologist,  Indianapolis  Nevada,  Reno 

359 


360  ELEMENTARY  ENTOMOLOGY 

New  Hampshire,  Durham  Pennsylvania,  State  Zoologist,  Harris- 
New  Jersey,  New  Brunswick  burg 

New  Mexico  South  Carolina,  Clemson  College 

New  York,  Geneva  South  Dakota,  Brookings 

Cornell  University  Agricultural  Ex-  Tennessee,  Knoxville 

periment  Station,  Ithaca  Texas,  College  Station 

State  Entomologist,  Albany,  N.Y.  Utah,  Logan 

North  Carolina,  West  Raleigh  Virginia,  Blacksburg 

State  Entomologist,  Raleigh  Washington,  Pullman 

North  Dakota,  Agricultural  College  West  \'irginia,  Morgantown 

Ohio,  Wooster  Wisconsin,  Madison 

Oklahoma,  Stillwater  United   States   Department  of   Agri- 
Oregon,  Corvallis  culture.  Bureau  of  Entomology, 

Washington,  D.C. 


III.    A    LIST  OF  BOOKS   FOR   THE   REFERENCE   LIBRARY 
General  Extomologv 

COMSTOCK,  J.  H.  A  Manual  for  the  Study  of  Insects.  (Comstock  Publishing 
Co.,  Ithaca,  N.Y.,  1895.) 

Comstock,  J.  H.  and  A.  B.  Insect  Life.  (D.  Appleton  &  Co.,  New  York 
City,  1 90 1.) 

FoLSOM,  J.  W.  Entomology,  with  Special  Reference  to  its  Biological  and  Eco- 
nomic Aspects.    (J.  B.  Lippincott  and  Co.,  Philadelphia,  Pa.,  1906.) 

Howard,  L.  O.  The  Insect  Book.    (Doubleday,  Page  &  Co.,  New  York,  1904.) 

Kellogg,  V.  L.  American  Insects.  (Henry  Holt  and  Co.,  New  York, 
1905-1908.) 

Packard,  A.  S.  A  Text-Book  on  Entomology.  (The  Macmillan  Company, 
New  York,  1898.) 

Sharp,  D.  The  Cambridge  Natural  Histoiy.  Insects.  2  vols.  (The  Macmillan 
Company,  London,  1 895-1899.) 

(The  works  of  Folsom,  Kellogg,  and  Packard  above  are  especially  strong  con- 
cerning the  anatomy  of  insects.) 

Butterflies  and  Moths  (Lepidopterd) 

C0M.STOCK,  J.  H.  How  to  Know  the  Butterflies.  (D.  Appleton  &  Co.,  New 
York,  1904.) 

French,  G.  H.  The  Butterflies  of  the  Eastern  United  States.  (J.  B.  Lippin- 
cott and  Co.,  Philadelphia,  1886.) 


APPENDIX  361 

Holland.  W.J      The  Butterfly  Book.    (I)oubleday.  Page  &  Co.,  New  York, 

1905.) 
The  Moth  Book.    (I)oubleday,  Page  &  Co.,  New  \'()rk.  1903.) 
Eliot,  Ida  M.,  and  Sot'Li:,  Cako  C,  Caterpillars  and  their  Moths.    (The 

Century  Co.,  1902.) 
DiCKER.sox,  Mary  C,  Moths  and  Butterflies.    (Ginn  and  Company,  Boston, 

1905.) 

Economic  Ento.mologv 

S.MITH,  J.  B.    Economic  luitomology.    (J.  B.  Lippincott  and  Co.,  Philadelphia, 

1S96.) 
Sanderson,   E.   D.    Insects   Injurious  to   Staple   Crops.    (John   Wiley  and 

Sons,  New  York,  1902.) 
Insect  Pests  of  Farm,  Garden  and  Orchard.    (John  Wiley  and  Sons,  New 

York,  1 91 2.) 
Chittenden,  F.   H.     Insects   Injurious  to  \'egetables.    (Orange  Judd   Co., 

New  York,  1907.) 
Saunders,  Wm.    Insects   Injurious   to   Fruits.    (J.    B.    Lippincott  and   Co., 

Philadelphia,  Pa.,  1883.) 


INDEX 


Abdomen,   7,    11,   25,   282;  of  female, 

283  ;  of  male,  282 
Acalypterae,  325 
Acanthidae,  114,  135.  309 
Accessory  organs  of  digestion,  291 
Acrididae,  81,  30S 
Actia  luna,  215 
Aculeata,  274 
Adalia  bipunctata,  162 
Adephaga,  137,  171,  312 
Adult,  53,  56 
Aeschnidae,  306 
Agaristidae,  318 
Agrionidae,  306 
Agromyzidae,  327 
Alaus  oculatus,  146 
Alcohol,  337 
Aletia  argillacia,  202 
Aleyrodidae,  311 
Allorhina  nitida,  152 
Ambush-bugs,  114,  135,  309 
American  acridium,  83 
Ampelophaga  myron,  211 
Amphibolips  spongifica,  247 
Anals,  24 

Anasa  tristis,  50,  121 
Anatomy  of  insects,  internal,  28 
Andrenidae,  267,  274,  321 
Angumois  grain-moth,  186 
Anisophaeridae,  305 
Anisoptera.  306 
Anisota  rubicunda,  212 
Anopheles,  223 
Anosia  plexippus,  179 
Antennae,  7,  1 1 
Anthomyiidae,  238,  242.  328 
Anthonomus  grandis,  168 
Anthonomus  signatus,  16S 
Anthrenus  scrophularia,  143 
Antlered  maple  worm,  195 
Ant-lions,  93,  307 
Ants,  243,  254,  274,  303,  320 ;  habits  of, 

255  ;  relation  of,  to  aphids,  255 
Aorta,  23 
Apanteles,  251 
Aphides,  107,  127 
Aphididae,  127,  135,  311 
Aphis-lions,  92 


36J 


Aphis  maidi-radicis,  129 
Aphis  pomi,  129 
Aphodius,  150 
Aphoruridae,  306 
Apiculture,  271 
Apidae,  267,  269,  274,  321 
Apina,  266,  274,  321 
Apple  leaf-hopper,  125 
Apple-leaf  trumpet  miner,  185 
Apple-maggot,  239 
Aptera,  73,  303 
Aquatic  bugs,  135 
Aquatic  sieve  net,  334 
Arachnida,  7 
Aradidae,  309 
Archips  cerasivorana,  187 
Archips  rosaceana,  186 
Arctiidae,  207,  217,  318 
Argentine  ant,  259 
Argynnids,  182 
Arilus  cristatus,  112 
Arista,  231 
Armored  scales,  132 
Army-worm,  202 
Arrangement  of  insects,  350 
Arthropoda,  6 ;  types  of,  284 
Articulata,  6 
Asilidae,  230,  242,  323 
Asparagus  beetles,  i  53 
Assassin-bugs,  112,  135,  309 
Atropidae,  307 
Australian  ladybird,  163 
Autographa  brassicae,  202 
Automeris  io,  213 

Back-swimmers,  135,  309 
Bacteria,  3 

Bag-worm  moths,  319 
Baiting  insects,  341 
Bark-beetles,  170,  171,  313 
Bark-lice,  307 
Barnacles,  7 
Bat-ticks,  242,  329 
Bean-weevils,  313 
Bedbugs,  114,  135,  309 
Bee-bread,  274 
Bee-flies,  231,  242,  323 
Bee-lice,  242,  329 


364 


ELEMENTARY  ENTOMOLOGY 


Bee-moth,  189,  217 
Bees,  5,  243,  266,  274,  321 
Beetles,  5,  136;  families  of,  137 
Belostomidae,  109,  135,  309 
Bembecia  marginata,  193 
Bembecidae,  262,  274,  321 
Bembecids,  274 
Beneficial  insects,  2 
Berytidae,  120,  135,  310 
Bibionidae,  323 
Big-eyed  flies,  325 
Bill-bugs,  169,  17'.  3 '3 
Bird-lice,  303,  307  ;  biting,  106 
Blackberry-gall,  247 
Black  damsel-bug,  114 
Black-flies,  226,  242,  323 
Blattidae,  77,  308 
Blepharoceridae,  226 
Blister-beetles,  166,  171,  311 
Blond  damsel-bug,  1 14 
Blood,  32 
Blood  vessels,  32 
Blow-flies,  236 
Blue-bottle  flies,  236 
Body  covering  of  locust,  275 
Body  structure,  10 
Boll  weevil,  2 
Bollworm,  202 
Bombyliidae,  231,  242,  323 
Bombyx  mori,  212 
Book-lice,  105,  307 
Borboridae,  327 
Boring  hymenoptera,  244,  274 
Bot-flies,  233,  242,  328 
Box-elder  bug,  121 
Brachycera,  229,  242,  323 
Braconidae,  250,  274,  320 
Braconid-flies,  250,  274 
Brain,  37 

Braulidae,  240,  242,  329 
Bristletails,  73,  74 
Brown  ant,  250 
Brown-tail  moth,  204 
Bruchidae,  158,  171,  313 
Brushes,  355 
Bud-borers,  217 
Buffalo-moth,  143 
Buffalo  tree-hopper,  124 
Bumble-bee,  270;  flower-beetle,  152 
Buprestidae,  146,  171,  312 
Burying-beetles,  142 
Butterflies,  5,  172,  174,  217  ;  four-footed, 
179 

Cabbage  aphis,  129 

Cabbage  butterfly,  178;  life  history  of, 

300 
Cabbage  looper,  202 


Cabbage-maggot,  238 
Caddis-flies,  93,  307 
Caecal  tubes,  31 
Calandra  granaria,  i6g 
Calandra  oryza,  169 
Calandridae,  169,  171,  313 
Callosamia  promethia,  216 
Calopterygidas,  306 
Calosoma  scrutator,  {39 
Calypterae,  328 
Campodeidae,  305 
Camponotidae,  256,  274,  320 
Camponotus  pennsylvanicus,  256 
Capsidae,  117,  135,  310 
Carabidae,  138,  171,  312 
Carnivorous  beetles,  137,  171 
Carpenter-ant,  256 
Carpenter-bee,  269 
Carpenter-moths,  191,  217,  319 
Carpet-beetle,  143 
Carrion-beetles,  142,  171,  312 
Catocala,  203 

Cecidomyia,  strobiloides,  228 
Cecidomyiidae,  228,  242,  321 
Cecropia  moth,  215 
Celery  caterpillar,  175 
Centipedes,  8 
Cephalothorax,  7 
Cerambycidae,  158,  171,  313 
Ceratocampidae,  319 
Cerci,  26 

Cercopidae,  125,  135,  311 
Ceresa  bubalus,  124 
Chain-dotted  geometer,  197 
Chalcididae,  253,  274,  320 
Chalcis-flies,  253,  274 
Checkered-beetles,  313 
Cherry-tree  leaf-roller,  187 
Chestnut  weevils,  168 
Chilocorus  bivulnerus,  162 
Chinch-bug,  120,  135,  310 
Chironomidae,  224,  242,  323 
Chitin,  27,  276 
Chloroform  bottle,  336 
Chrysalis,  48 
Chrysididae,  320 
Chrysomelidae,  153,  171,  313 
Chrysomyia  macellaria,  236 
Chrysopidae,  92,  307 
Cicadas,  122,  135,  311 
Cicadidae,  122,  135,  311 
Cicindelidae,  137,  171,  312 
Cigar  case-bearer,  185 
Cingilia  catenaria,  197 
Circulatory  system,  32,  293 
Classification,  67,  302 
Clavicornia,  141,  171,  312 
Clear-winged  moths,  192,  217,  319 


INDEX 


J65 


Cleridae,  313 

Click-beetles,  144,  171,  312 

Close- wings,  190,  217 

Clothes  moths,  1S6,  217 

Clouded  sulphur  butterfly,  178 

Clover-hay  worm,  18S 

Club-horned  beetles,  141,  171 

Coccidae,  129,  135.  311 

Coccinella  9-notata,  162 

Coccinellidae,  68,  161,  171,  313 

Cockroaches,  77,  308 

Cocoon,  48,  60 

Codling  moth,  1S7 

Coleoptera,  136,  304,  311  ;  families  of, 

311;   mounting  of,  348 
Coleoptera  genuina,  137,  171 
Collecting  belt,  331 
Collecting  coat,  330 
Collecting  forceps,  337 
Collecting  insects,  methods  of,  330 
Collecting  larvae,  339 
Collembola,  74,  305 ;  mounting  of,  344 
Colorado  potato-beetle,  153 
Complete  metamorphosis,  57 
Conopidae,  232,  242,  325 
Cordulegasteridae,  306 
Cordyluridae,  325 
Coreidae,  121,  135,  310 
Corimelaenidae,  116 
Coriscus  ferus,  1 14 
Coriscus  subcoleoptratus,  114 
Corisidae,  135,  309 
Corn  root-aphis,  129 
Corrodentia,  307 
Corydalus  cornuta,  90 
Cossidae,  191,  217,  319 
Costa,  24 

Cotton-boll  weevil,  168 
Cotton  square-borer,  179 
Cotton-stainer,  119 
Cottony  maple  scale,  132 
Coxa,  22 
Crabs,  7 
Crambinae,  190 
Crane-flies,  220,  242,  321 
Crayfish,  7  , 

Crickets,  85,  305  ;  music  of,  86 
Crop,  30 
Croton  bug,  77 
Crustacea,  6,  7 
Cubitus,  24 
Cuckoo-flies,  320 
Cucujidae,  143,  171 
Cucujus  clavipes,  143 
Culicidae,  222,  242,  321 
Curculionidae,  167,  171,  313 
Curculios,  167,  171,  313 
Currant-borer,  193 


Currant  span-worm,  199 
Currant  worms,  245 
Cutworms,  200 
Cyanide  bottle,  335 
Cydia  pomonella,  187 
Cydnidae,  310 
Cynipidae,  246,  247,  320 
Cyrtidae,  323 

Damsel-bug,  114,  135,  310 

Damsel-flies,  98,  306 

Darkling-beetles,  165,  171,  311 

Datana  ministra,  194 

Dermestes  lardarius,  144 

Dermestidae,  144,  171,  312 

Dermestid-beetles,  171 

Dexidae,  328 

Diaphania  hyalinata,  188 

Diaphania  nitidalis,  188 

Diastictis  ribearia,  199 

Diastrophus  nebulosus,  247 

Differential  locust,  53,  82  ;  habits  of,  54 

Digestive  system,  29,  290 

Digger-wasps,  260,  274,  320 

Diopsidae,  327 

Diptera,  18,  218,  305,  321  ;  characteris- 
tics of,  218;  mounting  of,  348;  sum- 
mary of,  242 

Diptera  genuina,  219,  242 

Dissecting  instruments,  354 

Dissecting  trays,  335 

Diving-beetles,  140 

Divisions  of  body,  276 

Dixa-midges,  226 

Dixidae,  226 

Dobsons,  90,  306 

Dog-day  harvest-fly,  122 

Dolichopodidae,  231,  323 

Dragon-flies,  98,  306;  mounting  of,  345 

Dragon-fly,  life  history  of  the,  299 

Drasteria  erechtea,  200 

Drosophila,  239 

Drosphilidae,  327 

Dynastes  tityrus,  152 

Dysdercus  suturellus,  i  ig 

Dytiscidae,  140,  171,  312 

Earwigs,  87,  307 

Echinoderms,  5 

Ecology,  2 

Egg,  45-  50 ;  laying,  56,  63  ;  mass,  58 

Elateridae,  144,  171,  312 

Elbow  pins,  348 

Elm  leaf-beetle,  154 

Elytra,  24 

Embryology,  1 1 

Emesidae,  113,  135,  309 

Empididae,  ;^2t, 


366 


ELEMENTARY  ENTOMOLOGY 


Empoasca  mali,  125 
Empoasca  rosae,  125 
Empodium,  22 
Enchenopa  binotata,  124 
Engraver-beetles,  170,  171 
Entomobryidae,  305 
Ephemerida,  95,  304,  306 
Ephydridae,  327 
Epicauta  vittata,  166 
Epilachne,  163 
Epitrix  fuscula,  156 
Eriocampa  cerasi,  245 
Esophagus,  30 
Eumenes  fraternus,  264 
Eumenidae,  263,  274,  320 
Euphoria  inda,  152 
Euplexoptera,  87,  304,  308 
Euproctis  chrysorrhoea,  204 
Euvanessa  antiopa,  63 
Eyed  elater,  146 
Eyes,  12 

Eye-spotted  bud  moth,  187 
External  anatomy  of  locust,  275 

Facets,  12,  40 
Fall  army-worm,  202 
Fall  web-worm,  208 
Families,  71 
Feelers,  1 1 
Femur,  22 
Field  kit,  330 
Fireflies,  147,  171,  313 
Flat-bugs,  309 
Flat-footed  flies,  325 
Flat-headed  borers,  147 
Fleas,  240 

Flesh-flies,  236,  242,  328 
Flies,  5,  218 
Flower-beetles,  152 
Flower-bugs,  1 14 
Flower-flies,  232,  242,  325 
Forceps,  354 
Forficulidae,  308 
Formicina,  254,  274,  320 
Four-lined  leaf-bug,  118 
Fritillaries,  182 
Frog-hoppers,  125,  135 
Fruit-flies,  239,  242 
Fruit-fly,  life  history  of,  301 
Fruit-tree  bark-beetle,  170 
Fulgoridae,  31 1 
Fungus-gnats,  227,  242,  321 
Funnel  trap,  the,  339 

Galea,  14 

Galerucella  luteola,  154 
Galgulidae,  308 
Gall-flies,  246,  320 


Gall-gnats,  228,  242,  321 

Gall-inhabiting  Hymenoptera,  274 

Ganglia,  28,  37 

Garden  web-worm,  187 

Gastric  caeca,  31 

Gelechia  cerealella,  186 

Genus,  68,  71 

Geometridae,  195,  217,  319 

Geometrinae,  199 

Giant  crane-fly,  221 

Giant  water-bugs,  135,  309 

Gizzard,  30 

Gomphidae,  306 

Gossamer-winged  butterflies,  178 

Granary  weevil,  169,  313 

Grape  leaf-hopper,  125 

Grape  phylloxera,  129 

Grape  thrips,  125 

Grapevine  hog  caterpillar,  211 

Grasping  Orthoptera,  78 

Grasshopper,     external     anatomy     of, 

275 
Green  apple  aphis,  129 
Green  bug,  129 
Green-fly,  127 
Green  soldier-bug,  115 
Green-striped  maple-worm,  212 
Green  tomato  worm,  209 
Ground-beetles,  138,  171 
Growth,  47,  54 
Gryllidae,  85,  308 
Guest-bees,  274 
Gypsy  moth,  204 
Gyrinidae,  140,  171,  312 
Gyropidae,  307 

Halictus,  268 

Halteres,  24 

Handmaids,  194 

Harlequin  cabbage-bug,  115 

Harlequin  milkweed  caterpillar,  207 

Hatchet,  337 

Haversack,  330 

Hawk-moths,  208,  217 

Head,  10,  11  ;  study  of,  276 

Hearing,  42 

Heart,  32 

Heliothis  obsoleta,  202 

Hellgramite,  90 

Hemerobiidae,  307 

Hemerocampa  leucostigma,  204 

Hemiptera,    17,    107,    135,    305,    308; 

mounting  of,  346 
Hesperidae,  31S 
Hesperina,  174,  217 
Hessian  fly,  228 
Heterocampa  gutivitta,  195 
Heteromera,  163,  171,  311 


INDEX 


367 


Heteroptera,  107,  135,  308 

Hexapoda,  8 

Hickory-borer,  160 

Hippoboscidae,  240,  242,  329 

Hog  caterpillars,  211 

Holorusia  rubiginosa,  221 

Homoptera,  122,  135,  310 

Honey-bees,  270 ;  anatomy  of,  287  ; 
life  history  of,  271 

Hop  merchant,  179 

Hornblower,  209 

Horned  passalus,  149 

Horn-tails,  246,  274,  319 

Hornworms,  209 

Horse-flies,  229,  242,  323 

House-fly,  i,  234,  242,  32S 

Humming-bird  hawk-moths,  211 

Hydrobatidae,  135,  309 

Hydrophilidae,  141,  171,  312 

Hymenoptera,  18,  243,  303,  304,  305, 
319;  characteristics  of,  243;  gall-in- 
habiting, 246 ;  larvae  of,  243  ;  mount- 
ing of,  348 ;  parasitic,  247  ;  plant- 
eating,  244;  stinging,  254  ;  summary 
of,  274 

Hypopharynx,  15,  279,  295 

Ichneumon-flies,  250,  274 

Ichneumonidae,  250,  274,  320 

Ichneumons,  243 

Identity  of  insects,  67 

Ileum,  31 

Inch-worms,  195 

Incomplete  metamorphosis,  50,  53 

Indian-meal  moth,  1S9 

Inflating  insect  larvae,  353 

Injury  to  crops,  2 

Injury  to  domestic  animals,  2 

Injury  to  household  and  stored  goods,  2 

Insecta,  8 

Insect  nets,  331 

Insect  pins,  343 

Insects,  and  disease,  i  ;  near  relatives 
of,  5  ;  classes  of,  67  ;  compared  with 
Arachnida,  2S6;  compared  with  Crus- 
taceans, 284 ;  compared  with  Myri- 
apoda,  2S5 ;  comparison  of  types  of, 
287;  external  anatomy  of,  10;  growth 
and  transformation  of,  45 ;  number 
of,  3  ;  structure  and  growth  of,  5 

Insect  traps,  339 

Integument,  26 

Intestine,  31 

Invertebrates,  5,  6 

lo  moth,  213 

Iridomyrmex  humilis,  259 

Isabella  tiger-moth,  207 

Isosoma  tritici,  253 


Japygidae,  305 
Jassidae,  125,  135,  31 1 
Jug-handle  grub,  209 
Jumping  plant-lice,  311 
June-bugs,  151 

Labeling,  349 
Labium,  14,  278,  294-297 
Laboratory  exercises,  275 
Labrum,  13.  277,  294-297 
Lace-bugs,  117,  135,  310 
Lace  wings,  307 
Lachnosterna,  151 
Lacinia,  14 

Ladybird-beetles,  161,  171,  313 
Lamellicornia,  148,  171,  313 
Lampyridae,  147,  171,  313 
Laphygma  frugiperda,  202 
Larder-beetles,  143,  312 
Larger  carpenter-bee,  270 
Larva,  47,  58,  63 
Lasiocampidae,  216,  318 
Lasius  niger  americanus,  256 
Leaf-beetles,  153,  171,  313 
Leaf-bugs,  117,  135,  310 
Leaf-chafers,  313 
Leaf-cutter  bees,  269 
Leaf-folders,  217 
Leaf-hoppers,  125,  135,  311 
Leaf-horned  beetles,  148,  171 
Leaf-miners,  217,  319 
Leaf-rollers,  186,  217,  319 
Leaf  worm,  202 
Leather-jackets,  220 
Lebia  grandis,  139 
Lecanium,  132 
Legs,  21,  280 
Lenses,  355 
Leopard  moth,  191 

Lepidoptera,  17,  172,  305,  318;  mount- 
ing of,  347  ;  summary  of,  217 
Lepismidae,  305 
Leptidae,  323 

Leptinotarsa  decemlineata,  153 
Leptocoris  trivittatus,  121 
Lesser  migratory  locust,  81 
Leucania  unipuncta,  202 
Leucocytes,  t,^ 
Libellulidae,  306 
Lice,  121 

Life  history  of  insects,  298 
Light  traps,  341 
Ligula,  15 
Limnobatidae,  309 
Liotheidae,  307 
Liparidae,  203,  217,  318 
Lobsters,  7 
Locust-beetle,  157 


368 


ELEMENTARY  ENTOMOLOGY 


Locust-borer,  i6o 

Locustidae,  83,  308 

Locusts,  81,  308;   internal  anatomy  of, 

290  ;  preservation  of,  275 
Long-horned  beetles,  158,  171 
Long-horned  grasshoppers,  83,  308 
Long-legged  bugs,  135 
Long-legged  flies,  231 
Long-tongued    bees,     267,     269,     274, 

321 
Louse-flies,  240,  242 
Loxostege  similalis,  187 
Lucanidae,  148,  171,  313 
Lucilia  caesar,  236 
Luna  moth,  2 1  5 
Lycaenidae,  178,  217,  318 
Lygaeidae,  120,  135,  310 
Lygus  pratensis,  117 
Lysiphlebus  tritici,  251 

Machilis,  74 

Macrolepidoptera,  191,  217 
Maggots,  219 

Malacosoma  americana,  57 
Malarial  fever,  i,  223 
Mallophaga,  106,  307 
Malpighian  tubes,  31 
Mandibles,  13,  278,  294-297 
Mantidae,  78,  308 
Mantids,  78 
Mantispidae,  307 
Mantis  religiosa,  79 
Marx  tray,  353 
Masaridae,  320 
Maxillae,  14,  278,  294-297 
May-beetles,  151 

May-flies,  95,  306;  mounting  of,  345 
Meadow-flies,  325 
Meadow  maggots,  220 
Meal  snout-moth,  189 
Meal-worm  beetle,  165 
Meal-worms,  217 
Mealy-bugs,  131 
Measuring-worms,  217 
Mecoptera,  93,  303,  304,  307  ;    mount- 
ing of,  347 
Media,  24 

Mediterranean  flour-moth,  189 
Melanolestes  picipes,  113 
Melanoplus  atlantis,  81 
Melanoplus  differentialis,  53,  82 
Melanoplus  femur-rubrum,  81 
Melanoplus  spretus,  82 
Melittia  ceto,  193 
Meloidae,  166,  171,  311 
Melon  aphis,  129 
Melon  caterpillar,  188 
Melophagus  ovinus,  240 


Membracidae,  124,  133,311 

Mesothorax,  20,  279 

Metallic  wood-borers,  146,  171,  312 

Metamorphosis,  complete,  46,  47 

Metathorax,  20,  279 

Milkweed  butterfly,  179 

Millers,  199 

Minutien-nadeln,  348 

Mites,  7 

Molluscs,  5 

Monarch  butterfly,  179 

Monomorium  pharaonis,  256 

Monostegia  rosae,  245 

Mosquitoes,  218,  222,  242,  321 

Mossy  rose-gall,  247 

Moth,  60,  172,  183,  217,  318 

Mounting  insects,  343 

Mounting  on  points,  348 

Mounting  on  slides,  351 

Mouth-parts,  11,  12,  277,  294  ;  suctorial 

type  of,  1 5 
Mud-daubers,  262 
Murgantia  histrionica,  115 
Muscidae,  242,  328 
Muscids,  234,  242 
Muscina,  234,  242 
Muscular  system,  36,  292 
Mutillidae,  261,  274,  321 
Mycetophilidae,  227,  242,  321 
Mydaidae,  323 
Mydas-flies,  323 
Myriapoda,  8 
Myriapods,  6 
Myrmeleonidae,  93,  307 
Myrmicidae,  256,  274,  320 

Nabidae,  1 14,  135,  310 

Naucoridae,  309 

Necrophorus,  142 

Needles,  354 

Negro-bugs,  116,  310 

Nematocera,  220,  242,  321 

Nematus  ribesii,  245 

Nepidae,  135,  309 

Nervous  system,  37,  292 

Neuroptera,  90,  304,  306 ;  mounting  of, 

347 
Nezara  hilaris,  1 15 
Nine-spotted  ladybird-beetle,  162 
Noctuidae,  199,  217,  318 
Nodus,  98 

Northern  grass  worm,  200 
Notodontidae,  193,  217,  319 
Notonectidae,  135,  309 
Notum,  21 

Nycteribiidae,  240,  242,  329 
Nymph,  50,  54 
Nymphalidae,  179,  217,  318 


INDEX 


369 


Oak-apple,  247 

Oak-pruner,  160 

Oberea  bimaculata,  161 

Oblique-banded  leaf-roller,  186 

Ocelli,  12,  39 

Odonata,  98,  304,  306 

Odontota  dorsalis,  157 

Oestridae.  233,  242,  328 

Ommatidium,  40 

Onion-maggot,  238 

Ophion  flies,  250 

Orders,  68,  71 

Orneodidae,  190 

Ortalidae,  325 

Orthoptera,  76,  304,  30S  ;  mounting  of, 

346 
Oscinidae,  327 
Otiorhynchidae,  313 
Ovipositors,  26 
Owlet-moths,  199,  217,  31S 
Ox-bot,  2 
Oyster-shell  bark-louse,  134 

Palpus,  14 

Panorpidae,  307 

Papilionidae,  175,  31S 

Papilionina,  174,  217 

Papilio  polyxenes,  175 

Parasita,  121,  135 

Parasitic  Hymenoptera,  274 

Passalus  cornutus,  149 

Pea  aphis,  129 

Peach-tree-borer,  192 

Pear  psylla,  127 

Pear-slug,  245 

Pea-weevils,  158,  171,  373 

Peddlers,  157 

Pediculidae,  30S 

Pelecinidae,  320 

Pentamera,  137,  171,  312 

Pentatoma  sayi,  1 16 

Pentatomidae,  114.  310 

Pepsis  formosa,  261 

Periodical  cicada,  122 

Perlidae,  306 

Pharynx,  29 

Phasmidae,  80,  30S 

Philopteridae,  307 

Phlegethontius  quinquemaculata,  209 

Phoridae,  323 

Phryganeidae,  307 

Phycitinae,  189 

Phyla,  6 

Phymata  wolfii,  1 14 

Phymatidae,  114,  135,  309 

Physopoda,  305 

Physopodae,  308 

Phytophaga,  153 


Pickle-worm,  188 

Piercing  mouth-parts,  295 

Pieridae,  178,  217,  318 

Pimpla  flies,  250 

Pinning  block,  344 

Pins,  343 

Pipunculidae,  325 

Pissodes  strobi,  168 

Plant-bugs,  116,  135 

Plant-eating  Hymenoptera,  274 

Plant-hoppers,  124 

Plant-lice,  127,  135,  311  ;  jumping,  127, 

135;  life  history  of,  298 
Platypezidae,  325 
Platyptera,  103,  303,  304,  307  ;  mounting 

of,  346 
Plecoptera,  97,  304,  306 
Pleurum,  21 

Plodia  interpunctella,  189 
Plum  curculio,  168 
Plume-moth,  190 
Podisus  spinosus,  115 
Poduridae,  306 
Poecilocapsus  lineatus,  118 
Polistes,  266 
Pollenization,  2 
Polygonia  comma,  179 
Polyphemus,  213 
Pomace-flies,  239,  327 
Poneridae,  320 
Pontia  rapae,  300 
Porthetria  dispar,  204 
Potato  flea-beetle,  156 
Praying  mantis,  308 
Predacious  bugs,  112,  135 
Predacious  diving-beetles,  171,  312 
Predacious  ground-beetles,  312 
Preserving,  352 
Preserving  insects,  343 
Prionids,  160 

Proctotrypidae,  253,  274,  320 
Proctotrypid-flies,  274 
Proctotrypids,  253 
Productive  insects,  2 
Prominents,  193,  217,  319 
Prothorax,  20,  279 
Protozoa,  3 
Proventriculus,  30 
Psammocharidae,  261,  274,  321 
Pseudoneuroptera,  95 
Psilidae,  328 
Psocidae,  105,  307 
Psocids,  106 
Psychidae,  319 
Psychodidae,  321 
Psylla  pyricola,  127 
Psyllas,  127,  135 
Psyllidae,  127,  135,  311 


370 


ELEMENTARY  ENTOMOLOGY 


Psythirus,  270 

Pteromalus  puparum,  253 

Pterophoridae,  190 

Ptinidae,  312 

Puddle  butterflies,  178 

Pulvillus,  22 

Pupa,  47,  60,  63 

Pupipara,  219,  220,  239,  242,  329 

Pyloric  valve,  31 

Pyralidae,  187,  217,  319 

Pyralids,  187 

Pyralis  costalis,  iSS 

Pyralis  farinalis,  189 

Pyrrharctia  isabella,  20S 

Pyrrhocoridae,  119,  135,  310 

Radial  sector,  24 

Radius,  24 

Railroad  worm,  239  . 

Rake  net,  334 

Raphidiidae,  307 

Raspberry  cane-borer,  160 

Raspberry  geometer,  199 

Raspberry  root-borer,  193 

Rearing  nets,  357 

Rectum,  31 

Red  ant,  256 

Red-bug,  119,  135,  310 

Red-humped  apple  caterpillar,  194 

Red-legged  locust,  81 

Red  milkweed-beetle,  161 

Red-necked  blackberry-borer,  147 

Reduviidae,  112,  135.  309 

Reproductive  system,  291 

Reptiles,  5 

Respiratory  system,  33 

Rhagoletis  pomonella,  239 

Rhinoceros  beetle,  152 

Rhodites  rosae,  247 

Rhynchophora,  137,  167,  171 

Rhyphidae,  321 

Rice  weevils,  169 

Robber-flies,  230,  242,  323 

Rocky  Mountain  locusts,  82 

Root-maggot  flies,  238,  242 

Rose-chafer,  151 

Rose  leaf-hopper,  125 

Rose-slug,  245 

Round-headed  apple-tree  borer,  160 

Round-headed  borers,  158 

Rove-beetles,  143,  171,  312 

Royal  moths,  319 

Running  Orthoptera,  77 

Sag  net,  333 
Saldidae,  309 
Salivary  glands,  29 
Samia  cecropia,  215 


San  Jose  scale,  134 

Sanninoidea  exitiosa,  192 

Sapromyzidae,  325 

Sarcophaga  sarracenia,  236 

Sarcophagidae,  236,  242,  328 

Saturnians,  212,  217 

Saturnoidea,  212,  217,  319 

Saw-flies,  243,  244,  274,  319 

Saw-horned  beetles,  144,  171,  312 

Saw-toothed  grain-beetle,  143,  144 

Sawyer  beetle,  160 

Scale  insects,  107,  129,  135,  311 

Scalpels,  354 

Scarabaeidae,  149,  171,  313 

Scarabasid  beetles,  171 

Scavenger-beetles,  313 

Scenopinidae,  323 

Schistocerca  americana,  83 

Schizura  concinna,  194 

Schmitt  box,  350 

Scientific  names,  68 

Sciomyzidae,  325 

Scissors,  354 

Sclerites,  21  ;  of  locust,  276 

Scoliidae,  321 

Scolytidae,  170,  171,  313 

Scolytus  rugulosus,  170 

Scorpion-flies,  93,  303,  307 

Scorpions,  7 

Screw  worm,  2 

Screw-worm  fly,  236 

Scutelleridae,  310 

Searcher,  139 

Senses  of  insects,  39 

Sepsidae,  325 

Serricornia,  144,  171,  312 

Sesia  tipuliformis,  193 

Sesiidae,  192,  217,  319 

Sheep  maggot,  2 

Sheep-tick,  240 

Shield-backed  bugs,  310 

Shield-shaped  bugs,  135 

Shore-bugs,  309 

Short-horned  flies,  229 

Short-horned  grasshoppers,  81 

Short-tongued  bees,  267,  274,  321 

Shot-hole  borers,  170 

Shrimps,  7 

Sialidae,  306 

Sight,  39 

Silkworm,  2,  212 

Silkworm  moths,  217 

Silpha,  142 

Silphidae,  142,  171,  312 

Silvanus  surinamensis,  143 

Simuliidae,  226,  323 

Siphonaptera,  240,  305 

Siricidae  246,  274,  319 


INDEX 


371 


Skippers,  174,  217,  318 

Slugs,  245 

Smell,  42 

Sminthuridae,  305 

Snapping  beetles,  144 

Snout-beetles,  137,  167,  171 

Social  bees,  270,  274 

Social-wasps,  264,  274 

Soft  scales,  131 

Soldier-beetles,  14S 

Soldier-bugs,  1 15 

Soldier-flies,  230,  242,  323 

Solenopsis  geminata,  259 

Solitary  bees,  274 

Solitary-wasps,  263,  274 

Sow-bugs,  7 

Species,  68,  70 

Sphecidae,  262,  274,  321 

Sphecina,  260,  274,  320 

Sphingidae,  208,  217,  318 

Spiders,  6 

Spider-wasps,  261,  274 

Spined  soldier-bug,  115 

Spiny  elm  caterpillar,  179;  the   life  of 

the,  63 
Spiracles,  34 

Spittle-insects,  125,  135,  311 
Spreading  boards,  345 
Springtails,  73,  74 
Squash-bug,  50,  121,  135,  310 
Squash-vine-borer,  193 
Stable-fly,  236 
Stag-beetles,  148,  171,  313 
Staphylinidae,  143,  171,  312 
Stegomyia,  223 
Sternum,  21 
Stigmata,  34 
Stilt-bugs,  120,  135,  310 
Stinging  ants,  256 
Stinging  hymenoptera,  274 
Stink-bugs,  114,  135,  310 
Stomach,  31 

Stone-flies.  97,  306;  mounting  of,  345 
Stratiomyidae,  230,  242.  323 
Strawberry  root-louse,  1 29 
Strawberry  weevil,  168 
Streblidae,  329 
Striped  blister-beetle,  166 
Striped  cucumber-beetle,  156 
Subcosta,  24 

Sucking  mouth-parts,  294,  296 
Suctorial  lice,  308 
Sugar-maple-borer,  160 
Suture,  276 
Swallowtails,  175.  31S 
Sweeping  net,  332 
Sympathetic  system,  38 
Synchlora  glaucaria,  199 


Syrphidae,  23 
Syrphus,  232 


242 


Tabanidae,  229,  242,  323 

Tachina-flies,  237,  242 

Tachinidae,  237,  242,  328 

Tarantula  hawk,  261 

Tarnished  plant-bug,  117 

Tarsus,  22 

Taste,  41 

Telea  polyphemus,  213 

Tenebrio  molitor,  165 

Tenebrionidae,  165,  171,  311 

Tent    caterpillar,    216;   life    history   of 

the,  57 
Tent-caterpillar  moths,  217 
Tenthredinidae,  244,  274,  319 
Terebrantia,  244,  274 
Tergum,  21 
Termes  flavipes,  104 
Termitidae,  103,  307 
Tetramera,  153,  171,  313 
Tetraopes  tetraophthalmus,  161 
Texas  fever,  2 
Thorax,  7,  11,  20,  279;   appendages  of, 

2S0 
Thread-waisted  wasps,  262,  274 
Thyanta  custator,  116 
Thyreocoridae,  310 
Thysanoptera,  308 
Thysanura,    74,   305 ;    mounting   of, 

344 
Tibia,  22 
Ticks,  2,  7 

Tiger  beetles,  137,  171,  312 
Tiger  moths,  207,  217,  318 
Tineidae,  184,  217,  319 
Tineids,  184 

Tingitidae,  112,  135,  310 
Tipulidae,  220,  242,  321 
Tischeria  malifoliella,  185 
Tmetocera  ocellana,  187 
Toad-bugs,  308 
Tobacco-worm,  209,  251 
Tongue,  297 
Tortoise-beetles,  157 
Tortricidae,  186,  217,  319 
Touch,  41 

Toxoptera  graminum,  129 
Trachea,  ^^ 
Transformations,  46 
Tree-hoppers,  124,  135,  311 
Trichodectidae,  307 
Trichoptera,  93,  304  ;  mounting  of,  347 
Trimera,  161,  171 
Trochanter,  22 
Trypetidae,  239,  242,328 
Tumble-bugs,  i  50 


zi-^- 


ELEMENTARY  ENTOMOLOGY 


Tussock-moths,  203,  217,  318 
Twelve-spotted  Diabrotica,  156 
Twice-stabbed  ladybird,  162 
Two-spotted  ladybird,  162 
Tympanum,  43 
Typhlocyba  comes,  125 
Typhoid  fever,  2 

Uranotes  mellinus,  179 

Vedalia  cardinalis,  163 

Veins,  of  wings,  24 

Velidae,  309 

Velvet  ants,  261,  274,  321 

Ventriculus,  31 

Vermes,  6 

Vertebrates,  5 

Vespa,  266 

Vespidae,  264,  320 

Vespina,  261,  263,  274,  320 

Vinegar  flies,  327 

Walking  Orthoptera,  80 
Walking-sticks,  80,  308 
Warble,  2 

Wasp-flies,  232,  242 
Wasps,  243,  260,  274 
Water-boatman,  135,  309 


Water  dip  net,  -^-^^t^ 

Water-scavenger  beetles,  141,  171,  31; 

Water-scorpions,  135,  309 

Water-striders,  135,  309 

Weevils,  167 

Western  cricket,  85 

Wheel-bug,  1 12 

Whirligig-beetles,  140,  171,  312 

White  ants,  103,  307;  work  of,  105 

White  grub,  151 

White-marked  tussock-moth,  204 

White-pine  weevil,  168 

Window-flies,  323 

Wing-covers,  281 

Wings,  23,  281 

Wire-worms,  146 

Wood  nymphs,  318 

Woolly  apple  aphis,  129 

Woolly  bears,  207 

Worms,  5 

Xylocopa  virginica,  270 

Yellow  fever,  i 
Vellow-necked  caterpillar,  194 

Zeuzera  pyrina,  192 
Zygoptera,  306 


ANNOUNCEMENTS 


COUNTRY  LIFE  EDUCATION 
SERIES 

Edited  by  Charles  William  Burkett,  recently  Director  of  Experiment 

Station,  Kansas  State  Agricultural  College  ;  Editor 

of  .  h/it-riiiT/i  Agrkulfiire 

A  SERIES  of  practical  texts  for  the  amateur  and  professional 
farmer  written  by  experts  in  their  respective  lines.  These  books 
aim  to  give  a  thorough  exposition  of  both  the  theory  and  the  prac- 
tice of  the  various  branches  of  farming  and  breeding. 

TYPES  AND  BREEDS  OF  FARM  ANIMALS 

By  Charles  S.  Plumb,  Professor  of  Animal  Husbandry  in  the  College  of  Agri- 
culture of  the  Ohio  State  University.   Svo,  cloth,  563  pages,  illustrated,  #2.00. 

PRINCIPLES  OF  BREEDING 

By  Eugene  Davenport,  Dean  of  the  College  of  Agriculture,  Director  of  the 
Agricultural  Experiment  Station,  and  Professor  of  Thremmatology  in  the  Univer- 
sity of  Illinois.   Svo,  cloth,  727  pages,  illustrated,  $2.50. 

FUNGOUS  DISEASES  OF  PLANTS 

By  Benjamin  Minge  Duggar,  Professor  of  Plant  Physiology  in  Cornell  Univer- 
sity.  Svo,  cloth,  508  pages,  illustrated,  $2.00. 

SOIL  FERTILITY  AND  PERMANENT  AGRICULTURE 

By  CvKiL  George  Hopkins,  Professor  of  Agronomy  in  the  University  of  Illinois  ; 
Chief  in  Agronomy  and  Chemistry  and  Vice  Director  in  the  Illinois  Agricultural 
Experiment  Station.   Svo,  cloth,  xxiii -1- 653  pages,  ;f2.25. 

PRINCIPLES  AND  PRACTICE  OF  POULTRY  CULTURE 

By  John  H.  Robinson,  Editor  of  Farm  Poiiltry.  Svo,  cloth,  xvi  +  611  pages, 
illustrated,  ?2.5o. 

SHEEP  FEEDING  AND  FARM  MANAGEMENT 

By  D.  Howard  Doane,  Assistant  .'\griculturist  in  the  Office  of  Farm  Management, 
United  States  Department  of  Agriculture,  and  Assistant  Professor,  in  charge,  of 
Farm  Management  in  the  University  of  Missouri.  i2mo,  cloth,  128  pages,  illus- 
trated, $1.00. 

Other  volumes  in  preparation 


174/4 

GINN   AND   COMPANY   Publishers 


A    TEXT-BOOK   IN   GENERAL 
ZOOLOGY 

By  Henry  R.  Linville,  Head  of  the  Department  of  Biology,  Jamaica 
High  School,  New  York  City,  and   Henry  A.   Kelly,   Di- 
rector of  the   Department  of  Biology  and   Nature 
Study,  Ethical  Culture  School,  New  York  City 


462    pages,   illustrated,   $1.50 


y^N  exposition  of  the  science  of  zoology,  presented  without  the  inter- 
/-%  polation  of  a  laboratory  guide. 
^  -^  Four  years  spent  in  careful  examination  of  the  original  sources 
have  resulted  in  a  book  filled  with  valuable  material.  The  authors, 
through  their  extended  service  as  teachers  of  biology  in  secondary 
schools,  are  well  equipped  for  the  task  of  writing  a  text-book  designed, 
as  this  one  is,  chiefly  for  high-school  use,  although  intended  also  to  be 
available  for  elementary  college  classes. 

The  structure,  the  physiology,  and  the  natural  history  of  selected 
types  of  animals  are  described  with  accuracy  and  in  language  easily 
understood  by  young  students. 

The  treatment  of  the  subject  is  broad,  and  the  inductive  method  is 
employed  so  far  as  each  class  and  phylum  of  invertebrate  animals  is 
concerned.  The  definition  of  a  group  is  not  given  until  the  student's 
conception  of  the  group  characters  has  grown  to  the  point  where  the 
definition  forms  the  fitting  end  to  the  logical  process  involved  in  the 
exposition. 

The  Insecta  are  discussed  in  the  first  chapters,  and  after  the  remainder 
of  the  Arthropoda  are  described,  the  other  invertebrate  phyla  follow  in 
a  descending  series,  ending  with  the  Protbzoa.  Then,  beginning  with 
the  fishes,  the  order  ascends  to  the  mammals  and  closes  with  man. 

A  large  portion  of  the  book  is  devoted  to  the  insects  and  vertebrates, 
because  young  students  are  more  familiar  with  these  groups  and  so  take 
greater  interest  in  them.  The  less  known,  however,  are  treated  with  care, 
the  different  features  of  morphology,  physiology,  and  relation  to  envi- 
ronment being  maintained  in  good  measure  throughout. 

The  book  includes  two  hundred  and  thirty-three  illustrations. 


GINN  &  COMPANY  Publishers 


71.  P 


-"jSTc" 


F-Xy 


